There are some nice videos online with clear instructions.... Or you can watch a few videos and mix them up and make your own style I do that.... Anyway,,, Good luck ! I hope it turns out delicious.
the Hallyu club at my college made it with seaweed, rice, bulgogi, yellow radish pickle, carrots, egg, and some other stuff I forgot. It was really good though! I hope you get the chance to try it.
my understanding is that gimbap is just a rice and seaweed roll with fillings. there seem to be some pretty classic fillings, but it seems the choice of filling is up to you! here's a recipe from a food author i like, maangchi.
here's her video for a classic gimbap: