I don't know where you live but most places you can look in the phone book for people that install trailer hitches they will be able to fix you right up and show you how to set everything.
That's a good suggestion.
Assuming you've already checked that the trailer itself is sound, floors, wiring, lights, tires, etc., this is what you need to do for your trailer, being as it's an older model:
1. Install a "Breakaway" kit. Your trailer is too old to have one, but most states now require it.
2. Change out the old plug for the newer, larger plug, or buy an adapter for it. Adapters are available for just about any configuration, but I recommend changing out the plug to match your vehicle's receptacle. Less chance of a bad connection.
3. Have all the bearings checked and re-packed. You'll likely end up replacing one or two, even if it's precautionary. Bearings are not expensive, but the labor is. It is not a hard job to do yourself, if you'll get a little instruction first. Just messy.
4. While they're re-packing bearings, have them check and adjust the brakes. Trailer brakes last a very long time, but they get out of adjustment as they wear. Normally, an adjustment is in order when bearings are re-packed.
5. Trailer Brake Controller for your truck. You may need an adapter, but for most newer vehicles it's simply a plug-in hookup and a couple screws to hang the controller under the dash.
Trailer brake controllers are essentially nothing more than a variable resistor. Buying a more expensive one doesn't necessarily mean you are getting a better one. There is no such thing as a more powerful brake controller. The power is simply the 12 volts your truck supplies. Most controllers have two adjustments, as noted above, one for setting a range, and the other for setting the brake sensitivity within that range. Buy the one that has the options you think you will like. I like one that has a lighted readout, so I can see the settings as I change them. Mine has a button for changing the range quickly, and a thumb-wheel for setting the sensitivity.
As for settings, read the instructions on your controller. For example if you are hauling a fully loaded trailer, you may want it on the highest range, say, range "D", to give you adequate stopping power. Then after you have unloaded the trailer and start home, you may want to select range "B", so that your trailer brakes don't lock up every time you apply brakes.
Within those ranges, you can set the sensitivity, so that you can feel how much brake the trailer applies as you brake. I set mine by applying the trailer brake without applying the truck brakes (there is a small knob or handle on the controller for this) and feeling how much braking I feel from the trailer. I set it so that I can feel the trailer brakes engaging well, but I do not set mine as stiff as the previous poster who likes to "let the trailer stop the truck". You can over heat trailer brakes easily and never know it, especially when you are running down a long hill. Let your truck do it's part as well.