Does anyone know the button combination? I bought the skill but I can't train it in the dilapidated shrine and there's nothing in the description to explain how to use it.

the game says LB+RB, but i cant seem to figure out how to use it..

You have to put the skill in the slot in the area where you slot your quick bar items

So I always end up using Whirlwind Slash because it just seems the best all round? You can be punished for it if you use it wrong, but it seems hard to mess up and when enemies feel difficult to punish whirlwind can at least get small amounts of damage through their guards. Would anyone mind recommending other Combat Arts to try out? Since I feel stingy with my points and i'd rather go for passive buffs than active use that might not be worth it

This thing rips emma apart if you spam it

Very good against big enemies like Drunkard, Guardian Ape, Chained Orge, deal quick burst damage faster and stronger than 2 normal slashes.

Perfect against mobs of weak enemies like in Mibu Village and the small dragons before you fight the Divine Dragon.

So apparently the little hop you do is considered a jump. You can use it to avoid perilous sweeps, but since it needs about half a second to get off the ground, you need to see the attack coming.

This is my favorite combat art for general play. You get it early, you get it cheap, it costs nothing to use, it's fast, it dodges over sweeps, and when you wander down the wrong alley and find yourself mobbed, it hits more than 1 jerk.
There are doubtless other arts that are better in specific situations, but for exploring new areas or fighting new bosses, whirlwind 4 lyfe.