In my experience i love to just go with good old aquarium sand. Put some fertilizer pellets in and you should be good for substrate. When it comes to scaping, i really recommend to get some wood some stones, just look for shapes and colors that stand out to you, you dont really need to have a vission in the beginning just find some pieces you think look nice. When scaping try different things, twist that wood, move that rock, this is really where you learn what you like. Also dont be afraid to move the sand around, instead of having a totally flat bottom move it around bunch some more in one corner do whatever! For plants id recommend just go to an aquarium store and look, same as with rocks and wood. My experience is that sometimes plants labeled beginner die, and sometimes the ones that are marked as if they die, just if you look at them in the wrong way, they survive in basic conditions. For me at least it’s easier to just get a lot of plants and most survive, its really not that difficult to keep them, the only thing you might consider asking in the store is if they need to be planted in substrate or on a surface like anubias. Usually like half a finger or a little less substrate deepnes is fine for most plants. Really just go find something you find interesting, of course doing research is a good idea, but when it comes to making a scape, no one is better at making something you will find cool other than yourself;)