When you make a new map, you are greeted with 4 mapping formats at the prompt. (Shown editor is Ultimate Doom Builder) These are the default formats. You can change the default formats and select other formats to map in, but now is not the time for that.   Doom: Doom 2 (Doom Format), or Vanilla/Doom Format, is the most basic format. ID Software's maps were made in this format. As long as you are using a limit-removing source port (majority uses one) you will be fine runn