Basis
HH is a weapon specialized in blunt damage, allowing it to stun the monster to create openings if you focus your attacks on its head.
It can also enter Performance Mode, allowing it to play music notes. Pairing the right notes plays a song granting you and your allies buffs. Each HH has 3 notes determining the songs it can use. Frontier doesn’t really have a good ingame tool to see what songs you have access to, aside from a book in Your House library (but it doesn’t filter based on your notes). The current best solution is on Wycademy, with a tool listing songs based on your available notes.

Earth Style
Frontier HH can perform a sonic bomb at neutral. Aside from the sonic effect, the sonic bomb hit nearby players, being able to cancel a status and triggers Red Soul and Blue Soul skills.
In Performance Mode, HH can also perform an encore if you have a valid song in your music track (if you play white-red you get an Attack Up song that can trigger an encore but if you play white-red-red, the encore will fail).
Heaven Style
Heaven Style replaces the pounding attack for a rising stab one that can be infinitely chained. This is the most efficient HH combo.
Storm Style
Storm Style introduces the sakura note that can replace any note in Performance Mode. This note grants you new songs notably for Purple – Cyan – Red HH which can now use the Attack L (purple-red-red, purple-red-sakura or purple-cyan-sakura) and Element Attack (cyan-sakura-purple) songs.
Extreme Style
Like for every weapon, Extreme Style allows you to run with HH.
HH can now charge the smaller HH at the start if its music track by hitting the monster. Once the gauge is filled, playing the same note twice will add a square around said notes. You can then use your sonic bomb to inflict debuffs to the monster based on the note color for 90s. The white and purples notes increase the monster’s raw hitzones by +2, the sakura note will prevent the monster from fleeing while the other notes increase the monster’s elemental hitzones by +4 (red fire, blue water, yellow thunder, cyan ice, green dragon).
Daily bonus
The Daily bonus double the song durations, synergizing with the Flute Master skill.