Tail heavy is what it sounds like. In all kits and plans they show the CG with the +or- but I have never had an ARF but I would bet they showed you. Well, I do have an ARF but I'm the third owner and never saw any plans or instructions but figured out the CG.
Tower has A nice CG machine and it's good for most models. If you don't have one you should buy one or make one yourself.
In my case by adding the 40cc gas engine I knew I was going to be nose heavy. While still in the bones I put the plane on the machine and moved my gear around until I got the CG as close as I could. I had to install everything as far back as I could. When complete I put the plane back on the machine and found I was three ounces nose heavy. For A 15 pound plane that wasn't too far off. A good flying plane is all in the set up and having A straight plane.
Good luck