For starters, you'll only need to shift to Drive (D) and just use the accelerator to go forward, and of course to slow down gradually, ease up on it, or release it all the way depending on how slowly or quickly you want to slow down. Use the brake pedal, obviously, for quicker braking/stopping. In case you need to use engine brake, you may shift down from D to 3, or 2, or L, depending on your current speed (the gears have upper limits, so try to memorize them).

Obviously, to go backwards, shift to R. Remember to use the shift knob when shifting to and from R (Reverse) and P (park). You also need to press the shift knob when downshifting from D to 3, 3 to 2, 2 to L. You may shift safely from N to D and vice-versa even when the vehicle is in forward motion.

Read the manual for more driving tips...

Hope this helps...