I'm not totally sure if I understand the question! If you're asking for tips on writing the beginning of your story, here are a few suggestions:
A. Your character can walk into a guild office and register directly with the guild. You can check the
Adventurer's Guild entry on the
Library to see some notes that other players have added from their own stories. Generally speaking, you are allowed to make up your things, so you can always invent a receptionist character to interact with, or you can use a receptionist that someone else made. You can also leave these kind of details vague in your story (i.e. unnamed receptionist).
B. If you don't want to physically walk into a guild office, you could have your character recruited to the guild by some kind of wandering agent.
C. You could also skip the guild registration scene completely. Introductions are sometimes annoying to write, so fast forwarding through your story to after they registered is totally fine as well. You should write what interests you, so if you want to take quests, just skip directly to the quests! You can always go back to write an introduction if you want to (and you can reorder chapters on SH too).