Event cards have the name of the scenario they belong to typed on the bottom, and will say something like, “Event Encounter (Approach of Azathoth),” and they’ll also have a blue / grey color front, as well as a magnifying glass. Encounter cards will have no magnifying glass, and the front of the card is generally colored similarly to the color on the back of the card.
For reference this is explained on page 5 of the Learn to Play guide.

Are you asking how to tell the difference between the regular encounter cards for each neighbourhood and the event cards?
The text side is a different colour — the event cards have a bluish background. They also have a clue icon on them, and text (I think down the bottom) labelling which scenario they belong to.  

Exactly. That's the reason why I keep telling the game doesn't scale properly: even if the number of tokens is proportional to the players in the game, scaling still doesn't work because effects can snowball before investigators can react. One thing is:
a) Investigator A resolves their turn
b) Mythos for Investigator A
c) Investigator B keeps playing
and another one is resolving a chain of 12 tokens, especially when there's a reshuffling of the chaos bag in between so that you can pull two gate bursts on the same neighborhood in a row, or two reckoning effects. It's bonkers.
I'd suggest to go this way: 2 per player until you reach 6 tokens, then resolve an extra token per player. When you setup for 4+ players, remove a blank from the Mythos cup.

I'm guessing you're playing with a higher player count.  With 1-2 players it's pretty minor, with 3-4 it's a bit more aggravating, but with 5-6 you're going through almost the entire bag each time.
We draw all of them one-at-a-time, but we draw them all back-to-back-to-back.  We also split who does what: someone in charge of doom & gate bursts and assigning clues (handing them to whoever's not doing anything so they can shuffle them in to the top of the deck), someone else adds the doom/clue tokens to the board, someone else counts through the tokens in sequence.  It cuts down on the downtime.
As for overwhelming, the higher player counts are prone to bigger swings as the doom can overwhelm 1 or 2 areas of the board.  They can also respond more effectively (if they aren't all in a corner location) and clear 1 or 2 anomalies and clear (or nearly clear) the board of monsters.
Essentially, your trading for board control for increased doom accumulation.  You also have the ability to find clues at an accelerated rate.  It's a trade-off.
I think delegation and pulling tokens faster keeps people engaged.  If only 1 person is doing all the token placement and card manipulation, the rest of the players will feel the downtime.

Thanks Duciris for letting me know that way i could order sleeves for the game.

The contents I posted on a different thread, so I can provide them here!
Components
2 Scenario Sheets 4 Investigator Sheets Large Cards (159)
7 Headline Cards 20 Archive Cards (10 per scenario) 12 Anomaly Cards (1 deck for 1 scenario) 48 Event Cards (24 per scenario) 72 Encounter Cards (doubles each location deck) Small Cards (80)
4 Ally Cards 4 Item Cards 4 Spell Cards 28 Special Cards 12 Starting Cards (3 per investigator) 6 Wanted Condition Cards 22 Monster Cards Chits
Monster Deck Holder (in 5 pieces) 4 Investigator Tokens (with plastic stands) 8 "3 Clue/Doom" Tokens 7 "1 Clue/Doom" Tokens

Nope.  I'm using it all, Baby!!

I always use it all with Arkham files games. Generally if there are modular elements that shouldn’t be used they are pretty clear about it.

I want to Thank Everyone who help me. Today i Received the token and board for my Arkham Horror 3rd edition. From Fantasy Flight Games.

Also, keep in mind that the monster deck is not static: scenarios instruct to add monsters either by name or by type. So, if an expansion adds a new Nightgaunt, and you have a scenario saying "gather all the Nightgaunts", that Nightgaunt is added to. At this point, you'd be forced to get multiples of monsters coming with expansions too, and it's simply becomes impossible to keep track of it (even financially)

Agreed, unless you find someone who is going to sell out just that part from their copy then you probably aren't going to find another way besides this. FFG does not sell separate components. Maybe sort your monster deck by type?

I'd simply suggest to scan the cards and reprint those

1 core set.  Take advantage of FFG giving you a complete play set in 1 core for the first time and stop at 1.

Great stuff.  Glad it has been sorted for you!

I want to Thank Everyone who help me. Today i Received the token and board for my Arkham Horror 3rd edition. From Fantasy Flight Games.

I want to Thank Everyone who help me. Today i Received the token and board for my Arkham Horror 3rd edition. From Fantasy Flight Games.

I want to Thank Everyone who help me. Today i Received the token and board for my Arkham Horror 3rd edition. From Fantasy Flight Games.

I want to Thank Everyone who help me. Today i Received the token and board for my Arkham Horror 3rd edition. From Fantasy Flight Games.

I think you meant to post this in the LCG board as it hasn't been introduced into the board game. From my interpretation it appears that it only works for the extra action that you get this round. hence the wording
"you may take an extra action this turn, during which you get +2..."
I think the key word is during. Hope that helped some.

Got a notice from FFG that they are looking into the situation so hopefully i will See what Happens i want to thank everyone who help me out.

Good luck with it.  I hope it's sorted quickly for you.

Got a notice from FFG that they are looking into the situation so hopefully i will See what Happens i want to thank everyone who help me out.

No worries, mate I think something got lost in translation, but boards and tokens should be on your way, right?

I'd report the game store to FFG.
Here in Australia, you can go to Fair Trading or the ACCC to report places that refuse refunds for faulty goods.  We have reasonable consumer rights here.

I feel like I will enjoy 3rd edition much more when there are more scenarios and investigators to choose from. Right now, with the core scenarios and limited pools of encounter cards, I really do not feel like replaying most of them. It's strange really because I replay Arkham the Card Game regardless of the fact that there is a bit of a linear story.
I think the real problem for me are some of the stats. It feels as if you only need Observation, Lore, and Combat. The other two do very little and so investigators who have high will or influence simply feel worse than other investigators. They are not better at different things... they are just worse at the things that matter.
I want to see unique ways to use influence and willpower to some effect that is useful whether that is picking up clues, researching them, or removing monsters or doom.  Maybe there could be some kind of action that disrupts the power of a gate burst by playing with the mythos discard or something. I dunno. 
I love the smaller microcosm present in AH over eldritch, but something just feels a bit bland to me in 3rd ed. Like I noted, it's probably just the variety of encounters or the fact that each investigator starts out with very viable options to finish the scenario. There's very little need to explore and look for new items etc so there is very little feeling of increasing your character's ability to deal with things. They're just kind of flat and your success mostly relies on token pull luck (and tracking what has been pulled already etc).