First, you have to open a giveaway. Go to the Giveaway section and start service giveaway there. Describe what is the giveaway prize, choose how many winners Staff will pick, and wait for at least 72h and then tag Staff members to pick the winners for you. Once the winners confirm they got the prize and vouch on the thread you can start selling thread and wait for the Staff to approve it. Make sure to attach a giveaway link on that selling thread.