Hi Rob, your keys might already be in PEM format. You can open them in a text editor and if they begin with -----BEGIN CERTIFICATE----- then you're okay.
If you really need to format your certificate into PEM, then run: openssl x509 -inform DER -outform PEM -in server.crt -out server.crt.pem
For the intermediate certificates you need to check the certification path of your domain certificate, see picture.
Then you need to open each of these certificates in your text editor, and copy the -----BEGIN CERTIFICATE----- text etc. into the intermediate certificate section in sprintr. You can have multiple certificates in this field on sprintr.
Hope this helps
Use the command openssl pkcs12 -in allappsgoudsenl_cert.pfx -out allappsgoudsenl_cert.cer -nodes and use the created file.