How do i contribute?

You just giveaway games.

go to giveaways. click create a give away. select when to start and when to end. select the game of the name u giving away. send it through steam or email.

Buy a game as a gift from steam,
Create giveaway for that game
when the giveaway ends, gift the game to the winner
(the bold part is the most important part)

First thread at the top, stickied. The FAQ. Read it, and an answer you shall find.

"create a giveaway"

seems pretty self explanatory...

Hopefully the OP knows how to get back to this thread. He/she may never see our replies!

it's easy, see that giveaway drop down menu at the top?
click on it and select create a giveaway.
from there, you'll be taken to a different page that you'll need to fill out.
select which game you want to giveaway and how many copies you want to giveaway.
it's kind of self explanatory so i won't explain all of it.
when you are finished with it, click on create your giveaway and after reviewing your giveaway, click confirmed.
then wait until you get a winner and give him the game and poof, you are now a contributor.
please note that you have to get the game for steam to the winner.
in no way will steamgifts supply you with the game to give to the winner.

Perhaps he can not contrib anymore, he has deleted his 1 and only giveaway... perhaps 0 are avaiable