on this forum, you have two options for joining signature campaigns.
better option: go
HERE choose a signature campaign that accepts newbie rank and join it by following its instructions.
after a while your rank goes up and you earn more by posting.
other option:
buy an account with your bitcoins to be able to join better campaigns and earn more.
be careful not to get scammed.
and always follow the rules and be careful!
None of the signature programs for newbies are really worth it, in my opinion. The highest paying one is the 64blocks one which pays 0.00005 BTC per post with a maximum of 50 posts per week. A very prolific poster might reach this limit and make 0.00005*50 BTC which equals 0.0025 BTC. Yet that amount of BTC is only worth 60 cents.
If someone decides to join a signature campaign as a newbie, they shouldn't view it as a serious way to earn BTC. Instead, they should think of it as an educational experience similar to faucets. After all, the amounts involved are pretty much the same.