I'm making music and would like to know how do I make my bass guitar loop until I want a chord change, and it loops until the next chord change that I make ?

You would assign an Arpeggio Phrase to the Bass Part of a Performance. You can have it so that the lowest note played will trigger the KEY for the Bass line. You can set a split point that determines which Notes control the key transposition of the Bass line.

A Performance allows you to setup multiple Parts (a maximum of four) — some for real-time control others under control of an Arpeggiator.
There are many examples of this among the factory program set. And, of course, you can build your own.

You can designate the left side of the keyboard to ‘control’ the Bass Arp, while a second Part is used to play the Keys with the right hand. I highly recommend you play through some factory Performances to get an idea of how flexible this can be:

Recall the Performance “Smooth it Over” USER 1 G12(108)
Part 1 – Hyper Standard Kit (Drums w/Arp Hold)
Part 2 – Mega Finger + Slap (Bass w/Arp Hold)
Part 3 – DynoStraightMW (left hand chords)
Part 4 – Tenor Growl AF1 (right hand lead)

Recall the Performance “Chillin’ Keys” USER 2 G07(103)
Part 1: Hip Hop Kit 2 (Arp)
Part 2: Dark Bass (Arp)
Part 3: Analog
Part 4: Full Concert Grand
__ this four PART PERFORMANCE features Drums and Bass under Arpeggiator control, while PARTS 3&4 are a layered Pad across all keys for direct keyboard play. Notice the Bass (very simple) outlines the key by following the lowest note you play.

Thanks so much Bad Mister, I'll give that a try.