ElFrogio,
I used the Openvpn as per the link you posted but had issues with V8 & V9.
In the contribs section, Firewall Services has posted 3 variants to the openvpn scene. I have tried them all. They all work, are very reliable and they all have good instructions.
If you are using an Android tablet or iPad, you must use a routed configuration as those devices do NOT support the TAP adapter which is required for a bridged configuration. The most challenging part of the setup was the client on the android device, due to only scanty instructions and certificate management. Once I got my head around it, the task became very easy. PHPKi is an enormous help also. The end result is extremely reliable.
Whether you use a bridged or a routed configuration depends on your remote hardware and your requirements of a vpn. Unfortunately you do not include enough information in your post to allow further comment.
HTH
Peter