Well you posted, so you know how. Since you are new your posts will be moderated so they won't go up right away. If you stick around a while and post a lot, eventually you can ask to be unmoderated, then your posts will post instantly.  

Read the TER Instruction Manual, the top thread on this page, and read back on this newbie board a few pages. This should give you a lot of info about the hobby and this site. If you have more questions come back and ask here on the newbie board.  

If your post here was actually asking how to post an ad, then definitely read the provider ad posting guidelines which are found in the self help center or "TER Instruction Manual."

Welcome and good luck.