Where do I find my Bitcoin address in Coinbase?

In Coinbase you can create an address under:

> Account Settings > Bitcoin Addresses > + Create New Address

What do I need to do exactly to earn Satoshis through BTC Surf?

Click Browse Faucets

The startpage (first page you see) is probably not a faucet but a bitcoin related site. You can decide to join that site or just skip it by going to the next site. (Go to the next site by clicking the image that matches the word)

When you see a faucet you need to follow two steps:

Each faucet requires you to fill in your Bitcoin Address (so you can get credited) and to solve a catchha. After the faucet has given a confirmation message you can browse to the next faucet through the top menu (click the image that matches the text)

I hope the following video gives an clear example of this: