any good brake controlloler will mount under your dash and you can set the brake pressure for the trailer brakes. usually on a scale of 1-10.
When pulling my camper, I adjust it frequently depending if I am driving over mountains and such. You should adjust them so that you feel the trailer slowing down the truck.
If you don't have trailer brakes, it will be easier to put those on rather than put all new brakes on your truck. Also, make sure your truck brakes are in good condition....no air, good fluid, drums/rotor turned for even surface, check pads/shoes.