How to create a mobile directory account on macOS High SIerra? I forgot.

Server: High Sierra +Server. Client: High Sierra (still waiting for Apple to release the instructions to move to Open Source mail services as they promised a year ago)

I had to temporarily remove a mobile account from a client that is normally connected to my macOS High Sierra + Server. I deleted the account but saved the account home directory in a dmg.

Now I am unable to recreate the mobile account. It is possible to log in using the server's credentials, but the account doesn't show up in System Preferences. I recall one first had to create a network account by trying to log in, and then change that to a 'Mobile' account. But the network account is not created so I'm stuck. I'm unable to find the instructions anywhere.

I'd be obliged if someone points me to the right instructions.