If you’re installing something that won’t let you browse for certificates and instead asks for a thumbprint – e.g. Windows Admin Centre – you can get this using either the management console or PowerShell.
Simply run this command:
Get-ChildItem -Path Cert:LocalMachine\My
Open MMC (I usually hit Win+R then type in mmc), then click on File > Add/Remove Snap-in, then add the Certificates snap-in and select Computer account.
Now go to Personal > Certificates and you’ll see the certificates which are currently on the system.
Double-click the certificate you want to use, then go to the Details tab and scroll down to Thumbprint
Select the thumbprint string and copy it.