Put the mis file into .....1C SoftClub\il-2 sturmovik cliffs of dover - MOD\missions\Multi\Dogfight
Open the game, go to Multiplayer, Server, set up what you need there and click OK. Find and select the mission, which will load it. Then Start Battle to launch. It should show up in the server list for other players to join.
Hptm. Stecher, Staffelkapitän