Go in to your vietnam folder and make a custom folder if you don't have one in there create a new folder with the name of your map (example mcv_tutorial) and in that add the maps folder and it should look something like this :

If you have custom models and materials I recommend packing them in using VIDE also here is a tutorial if you don't know how to use it :

Start up your game and go to the workshop button. In there make sure you have Upload Map Selected. In there you just select your map from the custom folder that we made early and and then add your other info like this :