On the ARMA 3 Steam page, select the Workshop tab.
Find the Mod or Scenario you need, and subscribe to it by clicking the green plus button.
Launch ARMA 3.
On your local device, go to Steam/Steamapps/Workshop/Content/107410.
Open the folder with the unique Mod ID from the Steam Workshop.
Rename the file to “Mission.map.pbo“. “Mission” is the name of the mission from the Steam Workshop. “Map” is the map on which the mission is being performed.
Use the “Upload” button to upload the .pbo file from step 6.
Return to the main server folder /home/container/ and open the server.cfg file.
In the “//Missions Cycle” section, after “template =” replace the text of the mission name with the name of your .pbo file (here “…pbo” is not written at the end of the text).