Use Map Settings equivalent

Sorry for the noob question, but what is the way to make a "Use Map Settings" or equivalent map? Meaning it doesn't automatically assume that the starting point is a Town Hall, etc.

I want to make a sort of dungeon walkthrough type map, if you know what I mean. I can't manage it though as it stands, due to it thinking its a regular game map.

Open the trigger editor and delete the triggers, then it's not a melee map anymore.