User for One Domain with SSH Keys?

Virtualmin
1

System: Ubuntu 18.14. with about 8 virtual servers, all on shared IP

  1. I went to /home/##mydomain##
  2. Created a folder: .ssh # permission 755
  3. created file: authorized_keys # permission 644
  4. pasted in the pub keys from (e.g) Paul, Rajan, Arjun

Now I would let to give, for this one domain only (home/##mydomain##),
access via SFTP and ssh from terminal to just that one virtualMin server folder only: home/##mydomain##

I can get in because I have my pub key installed at /etc/ssh/… etc

ssh root@##mydomain##

I end up some the root directory (not /home/##mydomain##)

I want these users to log in and the only folder they can see is “/home/##mydomain##”

a) Do I Need to add them as users in VirtualMin?
b) There is no setting in the “Add Users” (for the one ##mydomain## VirtualServer, )

where I can say: “Allow this user access with SSH Keys”
c) in the terminal, what would they put?

sss ####@##mydomain##

?
SFTP is straight forward. Most FTP clients allow you to paste in the pub key into connection settings. That’s all there is to it.