IIS and OCSP Stapling

Hello, I have configured my web server for OCSP Stapling by following the steps described in this article: https://docs.microsoft.com/en-us/windows-server/security/tls/tls-registry-settings

But I still have two questions:

a) how does the serve receive requests from endpoints to obtain OCSP responses?

b) how does the server fetch OCSP responses to supply to endpoints?

Any help would be greatly appreciated.