Changing pedals is not difficult unless the existing pedals are totally glommed onto the bike.

Take care to note that they new pedals will be marked L and R, and don't mix them up. Be very careful to screw them in gently.

It's easy to do it right, if you have any resistance or if the pedal doesn't feel smooth when screwing it in, stop immediately, unscrew, and try again. Gently.

If you cross thread them, you'll probably end up with new crankset, and another set of new pedals. I have not yet had this problem, but my friend made a very costly mistake due to his impatience.