I will ask this here also.
in MTF I asked...
what is the secret that bio girls do and say and act in the powder room?'

what is it us MTF need to know?

what do you bio girls DO in the powder room?

By "power room", I assume you mean restroom.  Well, this is best answered by actually doing it, but I'll answer since I use it every day. 
They either:
1. Use the bathroom 
2. Touch up makeup
3. Talk
4. Wash hands

Thats about it.  It's pretty straight forward and nothing magical about it.

Melissa

well I am just concerned of the ''ettiquette" of it all and what is acceptable and what is a no-no.

Just act like a lady and you'll do fine.  It's kind of hard to say.  If you think of yourself as a "dude" and act like a "dude", then you may have problems.  It's hard to say because it just came naturally for me.  All I had to do is stop "acting".  I never took any courses or anything.  It pretty much just common sense I guess.  Treat others with kindness and respect.

Melissa