To change your own transmission fluid and filter you must get your vehicle off the ground. You can run it up on ramps or jack it up and put blocks under it. Be careful doing this so that it is stable and will not fall.
Have a large pan available to catch the fluid. Locate the transmission pan under vehicle. Loosen the bolts around pan. You might have to pry the pan loose from transmission with screwdriver or chisel. When pan is loose hold up and remove bolts. Carefully drop down and dump fluid into pan.
Clean gasket off pan or transmission. You might have to scrape with a chisel, or putty knife. Clean out the pan completely. Wipe out all the debris that might be stuck in the pan.
Take a ballpeen hammer and peen the bolt holes in the pan back. This will allow you to pull the pan tight to the transmission again. You do not want a leak.
Remove the filter from transmission. There should be a couple of screws or bolts holding this up. Install new filter in same way as you removed the old one.
Replace the pan to the transmission. Put the gasket on the pan and push in a few of the bolts. Start a few of the bolts in pan so it will hold it up loosely. Start all bolts. Tighten and torque down evenly.
Add required amount of transmission fluid. Make sure it is the right type for your vehicle. You can look this up in the cars manual. Check fluid level. This might require engine running. If fluid is correct you are ready to go.