I could use a little advice:

I read that I need to post 20 posts?...before I can go to a topic of my fancy, since this is my 2nd post what can I do for the other 18 posts? I know this may be a stupid question, but I can't just post another 18 introductions..or should I?

Another stupid question...how do I put a signature below my post?

Just read through the threads on the site and make some contributions, you will hit your 20 post's before you know it.

And welcome to ATS!

Don't post more introductions,just reply to threads that are ongoing.
Welcome to ats...you'll get the hang of it.