Depends on how the wifi is configured you need to have access to CA server (windows in this case)
Login for the user, for creating the certificate.
Policy to allow export of private key.
Download CA cert from server: https://server.com/certsrv
Convert CA.CER to PEM
openssl x509 -inform der -in ca.cer -out ca.pem
Create personal certificate from a Windows PC with mmc.
You need to have the template allow export private key
Convert your PFX to PEM
openssl pkcs12 -in roger.pfx -out roger.pem
User cert: roger.pem
CA certificate: ca.pem
Private key: roger.pem
Private key password: Password you set with the export och roger.pfx