Wow.. lots of questions. Most of which are pretty basic and the answers should be all over this board. My suggestion is to do alot of research...spend many hours reading this board.
You seem to be on track. 500mg Test Enan, 400mg deca, is a classic beginner cycle. Start them both at the same time (they take weeks to kick in). Run it for 10weeks.
As far as side effects, and anti-E's... I'll leave you to do the research on your own....
One other thing I wanted to mention: Personal Trainers are not trained in the world of steroids. While this one seems to know his stuff, I've seen advice from others that is way out to lunch. Make sure you double and tripple check all advice you are given.
RIP BigJim33 & GearedUp: You are sorely missed my friends.
Hindsight is always 20/20. But looking back it's still a bit fuzzy.