Forgot to say, in some countries like France, Belgium and maybe others the CAA needs to physically see the kit first (before you start) so they are sure it is a new kit and not an already assembled kit by someone else. If it is already built, you are not eligible to be the builder and you cannot do the maintenance on your own kit.
There are 3 inspections: before start, middle of assembly (mostly to see the drive train, controls etc) then final inspection. That is of course only applicable to aircraft that are authorised as a kit by that particular CAA. (see in detail one of my previous posts).