This is a quick what to do if you want to put this into GSM, open up my mod and look at the folders and files, then find the same locations in GSM while following the below:

Important step
1) resource > entity > -vehicle > tank_light> drag over the "lvt4_wb" folder over to GSM in the same location

2) resource > interface > scene > structure > drag over the "lvt4_wb" folder

3) resource > interface > scene > unit_icon and unit_icon_small > drag over the .tga image files

You'll need the Readme.txt in my mod folder for this bit

Important step
4) resource > set > interaction_entity > "tank.inc", open up this one from GSM and paste in the code which is available in the "readme.txt", look in my mods "tank.inc" to see where to place it, just search for "lvt4_wb" while it is open in a text editor

5) localization > "desc.lng" and "info.lng", open mine and the one in GSM and copy over the small bit of code for the entity names, search for "lvt_wb" while it is open in a text editor, there is also weapon type names you need to copy over into the "desc.lng", look in the "readme.txt" to see what it is

Hopefully this has helped, just to note that there can be some issues and i believe the GSM mod will wipe it if it updates itself.