How should I deal with my confusing first job, (details inside)

I’m a high school student with good grades and a busy athletic schedule. This summer I decided I needed to get a job and earn some money to save for college. Although I had literally no experience with the exception of babysitting, one of my father’s friends needed some help at his restaurant, so I went in to ask him about maybe getting a job.
The conversation lasted about two minutes; he told me to come in on Saturday at eleven to get a t-shirt and to “talk to the girls about what I’m suppost to do.” He gave me no other information, but seemed to be in a rush, so I just thanked him and left.
Well, today is Saturday, and not only is he not going to be there but I have no clue what he even wants me to do. He’s on vacation, so I don’t want to disturb him by asking what probably seems like stupid questions. I don’t know who “the girls” are, I haven’t filled out any kind of application, so the people who are there will have no idea who I am, and I really don’t know who to talk to when I get there today. This is my first job, so I’m really nervous and don’t know how to go about clarifying my confusion without sounding completely incompetent! Any suggestions?