General Registration Elastix extension Mac

Good morning,

I am trying to download Elastix extension on Mac but I don’t succeed…
I have read and tried through these explanations : https://github.com/SuperElastix/elastix/wiki/FAQ , https://discourse.slicer.org/t/error-with-new-extension-elastix/278 and https://github.com/lassoan/SlicerElastix
But it is as if I have done nothing…

Can someone explain me step by step what I have to do (I think that I download or load in Slicer in the bad way) ?

Thanks a lot in advance !

P.S. : Moreover, I have a little question : is it possible to save the outputvolume created with this module in a folder that I choose ?

Thanks a lot
Laura