I'm building an extension and have purchased doors, windows, and bi-folds. Now I'm trying to install them, but have never done this before and am confused on a few points:

- should the sill / threshold (?) of the bi-folds lay flush with the internal flooring and the external decking -- ie: so that you don't trip as you're walking through the opening?

- same question for the front door - should the threshold be level with the flooring? or higher?

- the thickness of the frames for all doors, windows and bi-folds is greater than the thickness of the wall frames -- will it look strange to have the frames sticking out beyond the external cladding?

Really confused here...