How to use Instabuilder 2.16 on already existing site?

I've started developing my site with avada (10h of work) and avada has some options that instabuilder doesn't, now I would like to do some changes with instabuilder which are hard to do with avada.
Anyone used instabuilder before and have any tips how to do this?

I am now very effective use it, the effect is not bad!

I am not work on this