There is no one program that you use to make or edit Halo CE maps. There are a suite of programs.
Fantasy World Generators
Halo Custom Edition Map Creator Fantasy Free
The process used to create a new map starts with creating the map geometry or Level BSP (Binary Space Partitioning) adding textures then exporting into a format that can be imported into the Halo Game. The HEK - Halo Editing Kit - is a suite of programs that contains the various tools you will need to import the map geometry and textures and allow for placement of other assets such as weapons, vehicles and scenery. Tool (tool.exe) Tool is a multipurpose command line program that compiles and converts data that has been exported from other sources such as 3D Studio Max. The data files that are created are referred to as 'tags'.
Running 'tool.exe' by itself with no command line parameters will display a complete list of the available command line parameters and appropriate variables and variable formats. Guerilla (guerilla.exe) Guerilla has a graphical interface that is used to edit the properties and resource references in the Halo data “tags”.
Halo 2 Vista game file resource - Halo 2 Vista game map files and utilities. Helipad Studios Game Development Team makes maps, modifications, and tags for Halo: Custom Edition. Contentsshow About Helipad Studios Game Development Team, was started in 2006, as a Cheat Code website, moving onto a Halo: Custom Edition modifying team, followed by becoming a more advanced.