Well i can tell you but its still going to be pretty hard to do.
Start buy finding your throttle linkage that is mounted to your injection pump. Under the linkage where it rests on the pump there is a set screw with a bolt running through it. You have to break the nut loose and then turn the bolt to move the throttle stop rest up. Then when you have it set at the correct idle tighten the nut. Also you will need to have a tachometer hooked up or some one in the truck with it runnning, in gear, with the a/c on. Your rpms should be between 850 to 900. The bolt is a 11mm if I remeber correctly. Having small hands and being double jointed doesnt hurt either!