1. Run the Installer and extraci in the main directory of the game (Usually: "x"*:\program files\steam\steamapps\common\company of heroes. (Where "X" is the hard drive where you installed or downloaded Company of Heroes with Steam)
From here, you can deceide between:
2. a, Only making B-Mod available every time you start it in Steam.
Go to steam, right click on Company of Heroes and click on "Properties". From there, click on "Set Launch Options...", and in that window, type: -mod Balance -dev
OR
2. b, If you want to have both vanilla CoH and the B-Mod simultaneously available for play without modifying the "Properties" section every time you want to switch, make a Shortcut --> Right click on the shortcut, select "Properties", there select "Shortcut" tab and add to the end of "Target" line the following text: -mod Balance -dev
It will look like this for example:
"C:\SteamLibrary\SteamApps\common\Company of Heroes Relaunch\RelicCOH.exe" -mod Balance -dev