Bushing out

At what time should i cut the top leaves to have my plant bush out

How about a couple of links for you to read up on it.....

https://www.rollitup.org/advanced-marijuana-cultivation/151706-uncle-bens-topping-technique-get.html

https://www.rollitup.org/advanced-marijuana-cultivation/200413-fimming-m-blaze-complete-how.html