Making a midi track play not from the beginning

Hi everyone,

I am new to GarageBand and the midi world. My problem is to be able to play a MIDI track of my composition not necessarily from the beginning, so that I can play over it even in the middle of the song if, for example, I want to keep a background note for the whole song.

To do this, I have tried exporting each MIDI track to WAV and re-importing it as audio so that I can play over it live, but it is very laborious.

Do you have any alternative solutions?

How can I play the Garageband instruments live without necessarily playing the takes from the beginning?

Thank you in advance for your help.