I want to export a recent recording I have done on Garageband to iTunes. But when I do so, it just gets uploaded from a random point of the song - not from the beginning. Could anyone please help me with this?

I love the sound and recording features of garageband. Is there a way I can use it on my Windows PC? The sound output is seen better than my Vox headphone mini amp but can’t seem to figure out a way to have garageband on windows.

Boss DC-2 Dimension C and Boss DM-2 Metal