Fortunately I am still young enough to remember what it is like to be new to this board (because it was a few weeks ago

It really helps if you've got some stories to share. If you don't, there's no point in membership because you can read the stories without being a member, and your account may be deleted for being a "lurker". If you don't have any stories that you can share (or you just want your real life experiences to be kept private), you could try writing some fictional ones. I resolved that I would write a true story first before embarking on anything fictional, but you don't have to be the same. People will give you feedback which will mostly take the form of encouragement (and requests for more) and constructive criticism. One thing that there is a push for these days is to say in the title who dominates who; for example, if you have a female tying up a male, put F/M in the title. All my stories will have this (but then, I've only managed to write one so far). If you have a multi-chapter story, post it in the same forum; don't start a new topic

Read whatever takes your fancy, and maybe give feedback yourself. Take part in any of the discussions that you feel like - it's a free country. And most of the people on here will be happy enough to point you in the right direction. I think that pretty much covers the basics.