There are so many things to do once all the caravans have joined, so let’s meet the Guildmarm first. She is incredibly important–through her, you take on quests either assigned by the guild, or requested by other NPCs.
She will relay to you all the information you need to be the best hunter possible. Through her you can take on and cancel quests, and progress through the ranks and tiers of quests.
When you talk to her, she will show you the quests classified by tier. Pick a quest and she will confirm it for you. If you decide not to take on the quest anymore, simply talk to her again to cancel. No skin off your back or hers, come again!