An armoury with an array of weapons, crates with scripts attached (BIS_fnc_arsenal), signs for you to place your Unit's insignias (or whatever) and two Armoury Guards just chilling in different rooms.
Tested & works in MP.
You can access the virtual arsenal by just walking up to a crate and selecting it in the context menu.
Copy the content of the Armoury (Interactive Arsenal) Compositions folder to: C:\Users\<username>\Documents\Arma 3\compositions
Changelog: (19-10-2020 - only displayed in news once every month)