In Lab or Proof of Concept environment it is not always possible or convenient to issue commercial certificates to perform tests or replace the default Exchange self-signed one.
In a previous post I have outlined the process of deploying a Private Certificate Authority in this post I will go in more detail on how to perform an Exchange Certificate Request.
The first step in the Exchange Certificate Request if of course generating the request itself.
Once you have CSR file open a browser and point to https:///CertSrv and click on the Request New Certificate link
Click on the Submit and Advanced Request and then on Submit a Request File
In the Submit a Certificate Request Page in the Saved Request text box paste the content of the Exchange Certificate Request file and be sure to select Web Server as the Certificate Template and finally click on the Submit button
Unless certificate issuance policies are in place that dictate otherwise, which should not be the case in a lab environment, the certificate will be issued immediately and you will be able to download and install it.
Once downloaded transfer the certificate to the Exchange server, complete the certificate request and assign it to services.