It works just by entering your Bitcoin address and get free Satoshi every certain time based on the faucet itself, sometimes there is a range of payment not fixed payment,

You can also use some sort of Bitcoin faucet rotators,it contains several Bitcoin faucets at the same page and you use your bitcoin address to claim from the first faucet then move to the next faucet in the same page till you claim your free bitcoins from all faucets,of course this is much easier and more convenient.

this is a good example of this rotators

Freedailybits

these are the easiest and most paying faucets,

Moonbitcoin

YOU decide how often to claim! Whereas most faucets only allow you to claim once per hour or once per day, we allow you to claim as often or as little as you like.

You may prefer to claim a smaller amount every 5 minutes, or visit once per day and claim the large amount that has built up while you were away!

Bonusbitcoin

Claim every 15 minutes Receive up to 5,000 Satoshi per claim Automatic 5% DAILY BONUS On demand, free withdrawals 50%lifetime referral commission

PlayBitcoin

Vote for the cutest animal and get 150 Satoshi every 10 minutes

Icebitcoin

Icebitcoin pays between 200-1500 Satoshi normally and 10,000 Satoshi every hour!

Water Bitcoin

Earn 275, 325, 400 or 1,000 Satoshi every 1 hour

ClaimBTC

Get free Bitcoin every 20 minutes!

Get also reward bonuses each time you claim,

Claim every day and get a bonus,For every consecutive day that you make at least one faucet claim, you will receive a % bonus. This bonus increases by 3% per day and by 5% each 5th day, up to a maximum of 100%,so you can double your faucet earnings!

FieldBitcoins

YOU decide how often to claim! Whereas most faucets only allow you to claim once per hour or once per day, we allow you to claim as often or as little as you like.

You may prefer to claim a smaller amount every 5 minutes, or visit once per day and claim the large amount that has built up while you were away!