I don't know the newer fuel injected engines that well, but the timing setup should be the same. Your best bet would be to pick up a Haynes manual for your truck and follow the directions.
Read about how to find Top Dead Center on the compression stroke for the #1 piston. You start from there. The timing mark on the cam gear must also be aligned with the pointer on the engine block under the timing cover.
If you pull the distributor cap you can verify that the rotor contact is at the #1 post to be sure you have TDC on the compression stroke.
Then you release the spring tensioner pulley under the timing cover with a large prybar or screwdriver and install the new belt.
Turn the crank pulley clockwise with the tranny in neutral and the e-brake on to make sure nothing is binding before starting it up again.
Good luck. It's not that hard, just methodical.
Its not as easy as that!You also need to take off the crankshaft pulley in order to put the belt onto the sprocket on the crank shaft.Also you cant simply turn your crank until the rotor aligns with #1 wire terminal , because if the belt is broken then the rotor wont turn , this is because the oil pump sprocket is independent from the crank sprocket, the oil pump sprocket is what turns your distributor.You can still turn the rotor manually though.
Unless it is a DIS ignition. Then you don't have to worry about the rotor. However DO NOT use anything but a harmonic balancer puller (i know it should go without saying..but...) because if it is a DIS then the Harmonic Balancer has very thin fins on it for the CPS. Once you get TDC and the balancer off..the new belt will slide right on and then reverse the steps
Just a minor point here, the 1990 2.3 will be a DIS.
My 1986 Mitchell manual shows a TFI module in the wiring diagram which would indicate the presence of a distributor. My 1990 Ranger is a DIS system so somewhere between 1986 and 1990 Ford went to DIS.