This might not be applicable; I know how to do it on the full sized Chevys, and I've fiddled around some with an S-10, so I believe it's very similar. If it's an internal fan model, it should be the same. There are 5 things to do: FIRST, before anything, disconnect the negative cable on the battery; you don't want to end up getting fried. Second, there's a lead from your battery to your alternator, an 8 gauge (usually red) wire that is connected on the back on a stud by a nut. Just don't drop the nut when you take it out; the stud is integral to the alternator. Third, there's an ECM connection on the lower left (looking from the front). Make sure you unplug this and don't strip it out or rip the wire. The 4th thing is the drive belt. Take it off by using a 3/8" ratchet or prybar to slack the tensioner, then just pop it off so it's off the alternator pulley. Last, there should be two 12mm or so bolts that mount the alternator to the block (and they're about 8" long). Take these off, and you'll have to pop out the alternator (it'll be stuck in their pretty good, use a rubber mallet or a padded prying tool). Presto, you just took out the old one. Installation is the opposite, and getting it into position might be tricky b/c the mounting bracket is a tight fit). Two notes: 1. make sure you have an adequate drive belt for the new pulley; they aren't always the same size. 2. Make sure the ECM connection is the same, as well as the mounting positioning.