What do I do in a hydrotherapy session?

Hydrotherapy treatment usually consists of gentle stretching, floatation and relaxation exercises, strengthening exercises against the resistance of the water and movement exercises within the water.

Do I need to know how to swim to have hydrotherapy?

No you do not need to know how to swim to be able to benefit from hydrotherapy. The pool has shallow areas, allowing you to exercise well within your depth. Flotation devices are regularly used, and there is always a physiotherapist in the pool.