All quest groups (diads or triads) start with the Main, non-repeatable quest, which unlocks the repeatable quests.
Tye Lahe is standing atop the dragon skull just north of Sagthorne Camp in Dragori.
About Daily Quests
About Public Quests
|Public Quests are infinitely repeatable. Those in Coast of Opportunity and Xaviera reward XP, TP, Gold, and an Old Bag (hence the common sobriquet, Bag Quests).
In all other zones they do not reward XP, TP or Gold, only Public Event Points. In all other aspects they are the same as a Daily Quest (except for the infinitely repeatable part and the rewards).