This article describes how to import a certificate from a PKCS12 file (files with extension .pfx or .p12)
Start the Command program, and type the command certmgr
Double click on Your personal certificate
The certificate window will show information about your certificate, see below
Choose “Details” tab -> “Copy to file…”
You should get the “Certificate Export Wizard” -> Next -> “Yes, export the private key”
Then you should get the following window and leave it as it is
Enter password to protect backup file
Choose location to save the backup file, and then click “Finish” in the following window
Finally you should get a message like below: