Only one choice here. You're now against the Harkonnen, helping the Fremen. You don't have to work too hard at this one - build up a reasonable amount of forces with the standard buildings and upgrades from above. The Fremen are down to the SE, so if you go essentially straight South, and then straight East, you get under the main Harkonnen forces and have an easy time crunching through their forces.

Dune 2000 Walkthough Index