First, you use the toilet to get rid of waste as you would a "regular" toilet. When you're done, you use the remote control or control pad to activate the wash function. Some bidets have temperature and pressure controls which you can adjust.
When you're done washing your private areas, you can use the air dry function on the control pad to dry off. You don't need to get up off the toilet seat to use the bidet function, but you might need to slightly adjust your position to make sure the water hits where you need it to.