The format of the file is fully described in the URL above.
You need to create a similar file with the specific data from your implementation.
The top part of the file is the contents of your .ovpn...
client
dev tun
proto udp
remote vpn.server.hostname 1194
resolv-retry infinite
nobind
persist-key
persist-tun
ns-cert-type server
verb 3
key-direction 1
<ca>
-----BEGIN CERTIFICATE-----
this part of the data is the Base64 encoded server authentication certificate's ROOT certificate
-----END CERTIFICATE-----
</ca>
<cert>
-----BEGIN CERTIFICATE-----
this part of the data is the Base64 encoded client authentication certificate
-----END CERTIFICATE-----
</cert>
<key>
-----BEGIN RSA PRIVATE KEY-----
this part of the data is the Base64 encoded client authentication certificate's KEY
-----END RSA PRIVATE KEY-----
</key>
<tls-auth>
-----BEGIN OpenVPN Static key V1-----
this part of the data is the Base64 encoded data from the .tls file
-----END OpenVPN Static key V1-----
</tls-auth>
to convert your .p12/.pfx file into usable text, you'll need to use openssl.exe:
openssl.exe pkcs12 -in certificate.pfx -out cert-data.txt -nodes
