Yes, you are in the right forum.You can apply the signature campaign from Bounties section and this the step to find it (just click) :
Bitcoin Forum > Alternate cryptocurrencies > Marketplace (Altcoins) > Bounties (Altcoins)

As I know the minimum requirement to join a campaign is the junior member and above but better you increase your rank asap because it affects in the division of stake.

Hope it can help