Hello and welcome.
I'm glad you asked!
Starting out the best thing will be to read a lot of the more recent posts, get know the active people here and when you feel comfortable join in discussions you find interesting.
As far as finding someone you can keep an eye on the Connect section. BDSM Personals are the more detailed personal ads, Short-form Personals are well, short ads and Online Play has posts relating to ads on things like kik, skype and so on.
I'd recommend before answering any ads you check out the profile including when the person was last active. This can save a lot of wasted effort if it turns out they haven't been here in months.
Have fun!