I was my single friends birth partner. i was there for moral support really, got her water, stroked her hair, held her hand, fanned her etc. The other thing we did, was talk through her birth plan and I agreed that if she really wanted or didn't want something I would help relay this. Also that if she changed her mind i.e wanted an epidural ,I would double check with her first.
Good luck, it was a fantastic experience, I hadn't even had kids at that point and it didn't put me off!