Your first post on the forum looks like someone who understands how you get merit to rank up. It's hard to explain how someone can sign bitcoin message when you're first getting to know the forum unless you're someone who knows how to use electrum beforehand to sign messages.

I'm not going to tell you much because there are a lot of responses you should read before me. This should be of use to you if indeed you really don't understand. Reduce activity on the bounty board and take more time to study and post something quality. Good luck.