Unless you have a very clear and specific question, you have to figure it out yourself depending on what you're trying to do.
Builds are tailored to fit their gamemode, there is no universal map.
For example if you want to make your own speedkart map, you could duplicate the kart spawns and win-brick onto a single plate, duplicate that plate, and then clear all bricks before replanting. Then save that and you have the necessary pieces. All that is left is to build your track.