Welcome to the board mate
I don't pct, just trt, so i'll let others advise you there.
However, for test enth, a "standard" cycle would be 500mg/wk for 12 weeks.
I see by your profile you decided to wait until you were 25, so good for you on that.
There is no "true" BF% number for when you should cycle. It is more like the higher the BF%, the higher the risk for sides. We usually advise to wait until somewhere 12 and 15% BF before cycling, but you'll have to be the judge on that one.

So let me ask you, what are the rest of your stats?
BF%
Years Training
Nutrition Experience - just checking to see how much you know about proper nutrition for lifting.

Anyways, hope that answers some of what you were looking for, others will advise soon

Cheers!
---Roman