Lighting a pilates studio with speedlight?

I am a complete novice when it comes to lighting techniques and hoping to gain some insight - a friend has asked me to take some promotional photos for her new fitness studio. I haven't seen the studio space but know there's no natural light, there's a wall of mirrors and she's asked 4-5 class participants to demonstrate various poses (it's a ballet bar workout). I only have 1 speedlight (SB700) and would love some technique advice. Can I make this shoot work for her with my equipment? If so, any specific tips? As I said, I'm a novice and still learning the use of my speedlight.

Many, many thanks!