Certificate for SSTP VPN server

I’m trying to set up an SSTP VPN on Windows Server 2019 Essentials (I was originally going to use L2TP/IPSec, but the company which manages our network infrastructure doesn’t support it). I’m new to this, so sorry if these are silly questions.

I think I’m OK until it comes to the SSL certificate. We have a domain, which is hosted externally and we have a gateway for our network which has a static IP address (let’s say, which is different from that of the domain. It isn’t clear to me:

  • What I need to name the connection on the server and on the client
  • What I need to name the SSL certificate
  • Where I get the SSL certificate from (we’re UK based)
  • Whether I need to install the certificate on the client as well as the server.

Really appreciate any help you can give me.