Installing Musi on New iPhone

Hi all.

Hope everyone is well. I have a question about installing Musi on a new iPhone upgrade. I’ve seen some post about it, but I’m still confused.

Can someone clarify this for me?

From what I understand, I go to Settings, then App Store, and then see “Offload Unused Apps” but am I suppose to turn it on or off or is there another step?

Also, does this transfer the data too?

Thanks in advance, and happy new years!