How to use a patch cord

This a patch cord

You plug it in the headphone input slot

Insert other side of the patch cord to this input device

It should look like this if you done the steps correctly

Go here

Go to sound

Select this

Go to GarageBand

Select new project an select podcast

Click that

Select real instrument

Click record an play your audio on the other device

Go to share an select this

Than export it

An there it is