I find it easiest to do it in these steps.
1) Front end up, battery disconnected.
2) Remove the AC fan for more clearance
3) Swing the power steering pump out of the way (up to the right) and remove the bracket
4) Disconnect charging cable and connector from the alternator.
5) Consult and study
Saturn Alt Install for where you have to grind. If you get an '01 Saturn alt, you may not even have to take anything off the alternator itself and it's only 1 wire to hook up.
The trick it so grind the block and rear part of the front cover to match the smallest part. (Make A match B)
Literally took me 2 minutes with a worn out grinding wheel on an angle grinder
6)Test fit as required. There is a compression fitting on one side of the alternator. I opened the gap up as much as I could while keeping that in for the test fit. If you can get the pivot bolt in and the belt on, you're golden. If not, keep grinding away.
Bolt up, route the belt and get ready for the fun part.
7) Tensioner bolt..... I've been able to use the stock set up with an additional bolt and locking nut (so the damn thing doesn't depart the vehicle....) There are many different thoughts on how to do this.
Personally, I like Jays the best, but I couldn't find a solid turnbuckle in my area.
8) Route the belt on the ribs closest to the alternator. The stock Saturn wheel has 5 ribs, but we only use 4. Who loves free ribs?!
9) for 95-98' DSMs, the single wire on the pigtail you got with the alternator (you did get that... right?) will hook up to the black/yellow wire on the existing connector. For'99s, it'll go to the blue wire.
I just used a spade connector and trimmed it to plug into the female DSM connector and secured it. That way if I ever wanted to go back to a Mitsu alt, it's a drop in. (not that I ever would though...)
10) Put everything back together, and make sure all the bolts on the alternator are tight. (ESP the tensioner bolt that attaches tot he alternator.)
11) Start up and enjoy that awesome bullet proof alternator.
None of the pictures are mine, But the setup is the same with exception to the alternator style.
Mine looks like this. The fan is now internal.