How to setup jailkit with multiple ssh users

Operating system: Ubuntu
OS version: 20.04

I wonder how to setup Jailkit in Webmin. I do have installed this Webmin Module, but as a leak of documentation, I don’t see, how to setup users for this jail.

What I try to do

I’d like to create a Jail for SFTP users. The Jail should be placed at /home/sftpUsers.
Each User should have their own login via SSH-Key, but shouldn’t see the other user-directories within the same level at sftpUsers.

Can anybody give me a hint, how to setup this ?