MaaS: Clients get the Image but don’t appear on the MaaS’s GUI under Machines

Hello Guys,
since a couple of days, I have been using the MaaS, it looks brilliant tool, but sadly there is less online know-how resources, especially the version 3.4. The documentations are also not much comprehensible.
Precisely: everything looks good, but when the clients get the Image, and the MaaS’s GUI doesn’t show the clients, why? of course I use all in VMs, but I think, it is an issue.
Second: i could not find any online documentation as well, how to configure the new clients, like managing their username, password, etc.
thanks a lot for your kind replies.
Anyone, who can teach me this tool professionally? i have a project, and i have not found any resource to learn this.
Best regard,