Put in fluid, start engine, shift to reverse and hold for 5 sec, then neutral and hold, then 3rd, 2nd, 1st.
Hold each gear for about 5 sec.
Then after you reach first do back to park stopping in each gear for a few sec.
Leave the engine running, check fluid level, add if needed.
No need to go through the gears again, you do it the first time to get the fluid to all of the valve's.
Always start by not adding how much you think you actually need, then slowly add more as needed.
Keep in mind it takes several minutes for the fluid to run down the walls of the dipstick tube and get into the trans so you will get a false reading if you check the fluid level to quickly after adding fluid.