How to Modify Halo CE Maps

1. Extract/decompile the map assets (Tags & Scenario) using HEK plus Note: Not all maps can be decompiled
2. Copy and/or rename the extracted Scenario tag to insure revision control
3. Add/delete tags using Sapien or modify tags using Guerilla
4. Compile the modified *.scenario file into a *.map file using Tool and then test in Halo CE

Blitzkrieg (blitzkrieg.dle) 
Blitzkrieg is the exporter plug-in for 3D Studio Max.  This plug-in exports the model data (vertices, materials, smoothing group information, animations, etc...) from 3DS Max to the file formats (.jms, .jmp, .jma, .jmm, .jmt) used by tool.exe to compile a data tag that can be used by Halo.

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”. 

Sapien (sapien.exe)
Sapien is used to edit or modify various aspects of a level that has already been compiled using Tool.   Sapien has a graphical interface that contains a 3D window that renders the game including the level bsp, models, and vehicles as well as playing sounds and running physics.   Sapien is used for many purposes, including the population of characters, weapons, items, scenery objects, and game play and mission objectives