Direct Access with Server Core edition - Imported new SSL certificate through Powershell but how do I replace?

Hello all,

I'm hoping someone can help. I have taken over the IT at a school where they use Direct Access. It was working perfect but unfortunately, the certificate has expired and now it's stopped working. The previous IT Manager used certify the web and let's encrypt to create certificates which lasted 90 days. I tried doing this but struggled so decided to buy a wildcard certificate for the domain. 

I have the certificate and have (hopefully) imported to the correct location, please see screenshot of how I imported..

What I’m struggling to do now is replace the certificate. I have some instructions from the previous Manager but I don't understand the first part Open "Remote Access Management" console

Is this a feature installed to the DA server that I need to launch? If so, what would the command be or is it a snap in/download and I do it from MMC?

Here are the instructions:

10. You can now replace the DA certificate: 

1. Open “Remote Access Management” console. 
2. Click “Manage a Remote Server” to the right. 
3. Enter the server name – da1 
4. Click “DirectAccess and VPN” at the top-left. 
5. Click “Edit…” under Step 2. 
6. Click Next. 
7. Click “Browse…” next to the “Select the certificate used to authenticate IP-HTTPS connections” box. 
8. Click “More choices” at the bottom-left of the dialog box that opens. 
9. Select the certificate that was just imported. 
10. Click Next. 
11. Click Finish. 
12. At the bottom of the window, click “Finish…” 
13. Click “Apply”. 

I've never used Core Edition, I have always used a GUI so am finding this very hard.

Any help would be greatly appreciated.

Many Thanks in advance