How do I get card drops in the Steam summer sale game?

It says on the page so here is what it says:

Craft a game badge

Starting June 1st, crafting a game badge earned you a Summer Sale trading card rather than a coupon, so if you crafted a badge in the last week you’re already ahead of the game. During the sale, each game badge you craft will get you an additional Summer Sale trading card.

Make a purchase

As an extra reward for purchasing, for every $9 USD spent during the sale, you’ll receive a Summer Sale trading card. From your Summer Sale badge page select “How do I get more cards?” to track your purchasing progress.

Play the Monster Summer Game

If you’re Steam Level 5 and above, you’ll get a Summer Sale trading card at random intervals while playing, up to three per 24-hour period. (If you reach Steam Level 5 before the end of the sale, you’ll be granted the cards you earned by playing the Monster Summer Game).

Trade for them

That’s why they’re called trading cards! Find friends with other cards and make trades. Your Monster Card badge page shows which friends have the cards you need.

Buy them from the Community Market

Sell the cards you don’t need and buy the ones you do, all with other Community members. Turn those duplicate cards into Steam Wallet funds to buy games.

Getting a card is actually not from playing the game. Each day you can get three by:

1. Starting a new game
2. Joining a friend's game
3. Beating the boss at level 10

I't says in the FAQ you have to be at least level 8 to receive any cards you've earned, and as long as you become level 8 by the end of the sale you'll receive them.