Does anyone can find some information about this?
Typically, bring yourself and your ID.
I've found that showing up early is OK; however, I've never been able to start the exam early. Showing up early gives me time to relax and study last-minute things. (You cannot take any study materials in.)
As to your other questions, they'll be answered when you're there. My experience has been:
I've been able to bring in bottled water. I don't take medication. I was able to use the restroom; however, the clock does not stop while you are away.