“You're all set.”
All set means completely ready or finished with a procedure. You're all set. is a standard way for airport staff to tell a passenger that everything is complete.
A1-59 / CEFR A1 / EPISODE 59
Asking the way to an airport gate
SceneTina is at the airport. She is leaving today. Frank is with her.

WORDS & CONTEXT
All set means completely ready or finished with a procedure. You're all set. is a standard way for airport staff to tell a passenger that everything is complete.
Still means even now, and kept is the past tense of keep (to hold on to). Frank is showing the souvenir Tina gave him in A1-51. Tina's it also refers to that souvenir: "You kept it."
Walk someone to a place means to walk with someone until they reach a place, and first means before anything else. Not ready for ... means not prepared for something; here, emotionally. Tina knows her gate is number five, but reaching it means saying goodbye to Frank, so she wants to delay a little by going to gate four first.