In the early game it's not too bad,
you can buy starter weapons of each class or make them pretty easily you start with the weakest of each weapon class, so you can give them all a shot, but it can be a significant investment to get a weapon from there to being endgame level. Personally I'd recommend watching a run through or two of the weapons to try and get a feel for what you might like and then tutorials on those from there. The game does have a training area which is handy for practising trickier moves without the threat of being eaten, but it's not the best for learning from scratch IMO.
More generally, there are the 14 weapon classes, each with completely different movesets and playstyles. They've all got a good amount of depth, so just taking one out blindly can be pretty rough, so most players will have a few classes they actually use and keep upgraded.
Within each class, the weapons have various branching upgrade trees. These usually all function similarly but have different stats, elements etc. Some of the more technical weapons have deeper changes between trees, but most don't.
Tier wise, the game is divided into low and high rank - HR has the same monsters again, but stronger, and with some new monsters thrown in (vaguely like some ARPGs repeat content again but harder). Armour shares these tiers, with low rank armour being basically obsoleted by its high rank variants, hence the previous advice on not grinding too much for LR armour. Weapons have a softer tier progression, with stronger weapon upgrades requiring materials from HR monsters.