r/FaceFusion

Complete n00b at how to install FaceFusion. A friend of mine installed it on my MacBook last year and then updated it to a newer version but sadly he's moved away so I can't get his help now. Currently have 3.5.0 installed but want to downgrade back to 3.3.0 as it ran a lot faster, 3.5.0 renders 3x slower for some weird reason and it's unusable for me. Can anyone point me in the right direction for a step-by-step n00b guide on how to downgrade to an older version? It would be much appreciated.