How to approach this girl?

I've (20m) met this girl (19) while being involved in the organization of a festival. We haven't really talked, or met a lot, we have just a seen each other a couple of times, and we know each others name, that's it.

This weekend, when the festival is happening, I will be away, not in the country. I won't really have an other occasion/chance to talk to her/get to meet her.

I'm a volunteer, and she is one of the coordinators.

What can I do? How could I ask her out, or just get to talk to her? I don't really want to just text her, because we didn't talk very much yet, and I don't think that it would look good from the perspective of the supervisors.

Any advice is appreciated.