How to get into hunts?

[Darkstride]

I'm not sure if you need to have the original hunts from your Grand Company unlocked first.

Either way, as the post above states, you need to go to the Forgotten Knight in Foundation for a very brief quest to unlock the level 53+ hunts.

On the clan hunt board:
Tier 1 hunts: daily, 3 seals each
Tier 2 hunts: daily, 4 seals each
Tier 3 hunts: daily, 15 seals each
Elite hunt: weekly, 100 seals

A and S Ranks spawn throughout the game's maps in semi-random locations. I believe each zone has 2 A Ranks and 1 S Rank. They are not always up and available, but they do reward you every time you kill them. A Ranks give you 40 seals and some tomes of Law, but I have yet to see an S Rank in Heavenward so I don't know what they give yet. I assume 100 seals.

A and S Ranks in pre-Heavensward areas will also give both Allied Seals (old) and a lower amount of Centurion Seals (new).

When you see a swarm of people spamming "invite me" in an area, it's likely to be an A or S Rank hunt, so join in and hurry up before it is dead. Reward credit is based on how well your party does with generating hate on the hunt, so solo won't give you a full reward only partial.