@Warspite:
Hang in there!!! RC square riggers are REALLY difficult to sail at the best of times.
The first requirement is a gentle but consistent breeze. swirling or gusting winds make it really hard to work out what you are doing.
Add a pennant on top of the highest mast, this may help to show you where the wind is from on the water
I found an oversize rudder helped a bit, but because the sails are the main source of power and steering you need to get the hang of where to angle the square sails to get it sailing across the wind. You may also need to balance the jibs against the spanker, or else one end of the boat will overpower the other. If you have the facility to furl some of the (higher) sails this may also help with control.
If it sailed backwards, that is great, that just means you had the sails on the opposite angle.
Also a square rigger will not sail upwind or close to the wind (unlike a Bermuda rig). While a Bermuda rig will sail within twenty or thirty degrees of the wind, with a square rigger, you will at best get it to sail about 70 degrees off the wind, so sailing upwind is a long hard job.
And finally, tacks are also difficult (turning the bow of the boat through the wind) until you get the hang of them; it took me hours of sailing to get one right and even then it remains unreliable. You have to do them a bit like a three point turn with a car in a narrow street - it involves sailing backwards part way through the turn.
For a start, you will find it MUCH easier to gybe (turn the stern of the boat through the wind)
Have another try sometime, they look great on the water....