Assessment process

I read something randomly and now it's totally freaked me out lol, can someone tell me what happens when you go for your assessment?  

I've filled out and sent the AQ10 form already, and I've been referred to a local mental health clinic in east London (I didn't know about being referred to the Lorna wing, which is good for adults, but it is a bit far for me anyway), I have support from my friend if there's any issue but I'm agitated not knowing about it now lol

So how long did it take, what did you do, anything you had to bring with you or talk about specifically etc. etc.