Build Fortnite edit?

If I e.g. B put a roof and a floor over me and set the floor last I can only edit the floor and not the roof because I only have to select the roof when building (hope you understand what I mean) can I somehow issue this?

Then get used to the ground first and then the roof is much better

It is not a question of when I set what, but that I can only edit what I have selected (e.g. If you are building a staircase that is still in blue then you only have to press r2 to build but you can only then edit the stairs and nothing else)

If I understand it correctly you keep the blueprint while editing and that is exactly the mistake I always take before I edit the pickaxe in my hand (almost everyone does it) or hold my weapon