you need a special tool to pull the balancer. it presses against the crank as it pulls the balancer out. it is a real simple job when you have the right tool.
assuming you have the tool:
I would probably remove the fan blade to make working in that area easier & less cluttered, then, loosen all the belt run accessories, remove the belts then remove the crank pulley, usually 3 or 4 bolts, probably1/2 or9/16 head, depending on the year, there is also one bigger bolt in the center , maybe 5/8 or larger, remove that, this bolt is what holds the balancer & pulley to the crank.
now you have access to the balancer. install the tool in the bolt holes that held the pulley on & tighten up the center bolt on the puller & as you tighten, the balancer will pull off.
What said above is correct. TO re-install there is a little keyway on both the crank amd the harmonic balancer. Make sure these are lined up and hand press on the crankshaft until it is tight. Then reinstall the center bolt and use its mechanical advantage to re-seat the HB. Reinstall pulleys and fan and you are done.
I usually screw the crank bolt (less the washer) back in before using the puller, less chance of messing up the crank snout or threads. Let the center bolt of the puller push against the crank bolt instead of the crank snout.
As long as you have the right tool, getting it off is the easy part (good tip from Dan). Installation can be a bit tricky to get the balancer bolt torqued to the correct setting without turning the crank as well. You can get it buy using a large screwdriver through the outer balancer holes and wedging it against the engine.
What STANG32 said. The center bolt of the dampner, if stock, will use a 15/16" socket. Before putting your puller on, BE SURE that you've removed both the bolt AND washer. Once I didn't realize the washer was still on there and couldn't figure out how come the puller wasn't pulling it off . It can't work if the washer is still on there.
Also, there's 2 types of pullers. There are the type that bolt to the dampner (this is what you want), and the "jaw" type that pull on the outer ring (this is the one you DEFINATELY DO NOT WANT). Using the jaw type puller will rip the outer ring off of the dampner, but not pull the dampner off of the crank.