easy, place folder into  (make some if neccsisary)              \company of heroes\WW2\Data\Scenarios\mp










shortcut your coh.exe 

(mine) C:\Program Files\Steam\steamapps\common\company of heroes\reliccoh.exe






target line         -dev


(mine)    "C:\Program Files\Steam\steamapps\common\company of heroes\RelicCOH.exe" -dev


run from shorcut
best to play with friend


same proccess is needed for each player