First, you posted on wrong place. You should ask these questions in This Board

Second, Campaign is like advertisement. You will be the salesman of that Project but you don't need to learn anything about the Project (maybe you need but just a little). You can post anything, but some campaign has rules that you can't post on some board like archive, etc. It means your post on those board won't be counted as qualified post to get paid. Usually you will get paid by Bitcoin, Ethereum, or Token, depends on the project.

Third, I think it's impossible to take part of multiple signature campaigns. Because the signature code is designed for whole signature space.