Going back a slide without a loop

I am coding up an online experiment, with a long set of instructions (about 16 slides). For efficiency’s sake I coded it up as a single routine with every loop presenting the next slide. However, I would like participants to go back to previous instructions and so I added a command that takes the look the opposite direction.

if key_resp.keys=='left':
    trials.thisN-=2

This works well in psychopy but not on pavlovia.

furthermore, i’ve seen solutions for going back that involves adding loops but do not want to re-write everything. Any solutions for pavlovia would be appreciated!

Hello,

really long instruction. Would that help? It is a different approach.

Best wishes Jens