First, I would advise you do more reading/research. As spending time on forums and reading a few books (ANABOLICS by William Llewellyn is a good start) on the subject should tell you more than enough. Secondly I hope you meant 250mg cyp e3d. 500 e3d is 2x what your first cycle should be.
As for your AI the only REAL way to tell is blood work. Some guys recommend you run your AI as needed while others will use it throughout. Since this is your first cycle and (hopefully) about 500mg/wk of test I think you should only run it when you see signs of high e2. Estrogen has many benefits to health and bodybuilding and it's not good to squash it like some guys will preemptively.
PCT should start 2 weeks after your last pin of cyp. If you're running BOTH nolva and clomid I would recommend Nolva 40/40/20/20 and clomid at 50/50/25/25 or even 25/25/12.5/12.5 would be sufficient.