Yeah, it can be a little tricky…. You need to push the looper a mesure before the loop is to start and a measure before it ends. You can push the loop button anywhere with the measure.

For an exercise start with 2 bar chord sequences such ii V ( songs like Oye Como Va) then try doing 4 bar sequences , 8 bar sequences , 12 bar blues, and so forth.

I do my loops on the fly, But the great thing is you can save your chord loops too!