Please help me setup terminal server or RDS.

Hi everyone, I need help setting up a terminal server / RDS VM.

I have approx. 20 users who will need to remote into a win10 client VM. So i am trying to setup a RDS on a VM (either datacenter 2016 or 2019).

1. can i run this from 1 VM?

2. Do i need a separate DC?

3. Do i need to purchase my own domain name ?

4. do i need to purchase a SSL Certificate?

Any help would be greatly appreciated, even a "dummies guide to setting up Terminal server"

thank you

Stephen