Help for replacing a thermostat

Hey, I'm getting ready to replace the thermostat in my 96 4.3 S10... I want to make sure I'm doing this right so I'm going to run my steps by you guys first so that you can tell me if I'm doing something dreadfully wrong...
1.) Let car cool
2.) Unscrew bolts on thermostat
3.) Take old therm. out and put new one in
4.) Put the housing back on... and done

I feel like I'm missing a step here tho.....

Also, how bad is it to put non Dex-Cool Coolant into the coolant tank?

I just changed mine a couple of weeks ago. I had to take off the serpentine belt, in order to get to your step two. It's a little cluttered there. Two gaskets, one o-ring type on the therm flange, and a regular one on the housing flange. I used gasket dressing on the second one. Take care in torquing the housing back on. DO NOT, I repeat, DO NOT put non Dex Cool coolant in there unless you completely flush out the system. You cannot mix the two different kinds of coolant, without disasterous results. Buy the Prestone flush kit. Basically a connection you add to the heater hose. It works well, just follow directions. Good Luck