openvpn 2.6.2 client config file for connecting to ssl vpn cisco firepower

[gogi1000]

i have a cisco firewall the firepower 1120. on workstations i have configured the anyconnect but i have a workstation with windows xp sp3. i cannot make upgrading to newer version os on this workstation. i installed the openvpn on this workstation and i need config file for ssl vpn on the firepower. can you give me some guide for configuring. i have not the ca.crt, the client.crt the client.key. my firewall just has the DefaultInternalCertificate. The firewall for authentication use Active directory.