Three things first

Before you can claim any sudokoin you need three things:

Stellar is a decentralized payment system that runs on lumens.
Getting a Stellar account is easy, but getting the minimum amount of lumens required to activate that account is a little more complicated right now (in short: you probably need to buy them).
We aim to provide a small tutorial at some time. Until then, read Stellar's F.A.Q. or our F.A.Q.!