I am trying to change the alternator in my 1993.

Tug on the belt and you'll see a 3" diameter pulley, probably plastic, move. That is the spring-loaded tensioner pulley. Use a box wrench to try to turn the center bolt. That will pivot the pulley and release tension from the belt.

Many mechanics use a shortcut to save time. As you release that tension, pull the belt up and off the generator pulley, release the tensioner, then use a rubber tie strap hooked to a hole in the hood to hold the belt up. That will prevent it from falling off any of the other pulleys. Turn the tensioner and lift the belt onto the new generator's pulley at the same time. That doesn't apply if you're installing a new belt.

Keep in mind that due to their poor design it is common to go through four to six replacement generators in the life of the car. To reduce the number of repeat failures, replace the battery at the same time unless it is less than about two years old. Due to their design, these generators produce huge voltage spikes that can destroy the internal diodes and voltage regulator, and interfere with the many computers on the car. As the battery ages it loses its ability to dampen and absorb those spikes.

Yup. As a former instructor it was important for me to use correct terminology. The industry has begun standardizing terminology since the mid '90s and "AC generator" is what they chose.

Chrysler developed the first AC generator and used it on 1960 models. They copyrighted the term so you will rarely find it in other manufacturer's service manuals. Others didn't develop their own "alternators" until beginning two years later on some brands.

The older style was a "DC generator" that worked differently and was incapable of producing even half as much current. When you use the term "alternator", everyone will know what you mean and no one will bring up this little factoid.