Remove the previous insole from your shoes
Trim (ONLY) the toe area of the 2620 insole to fit your shoe, (use your previous insole as a template)
Attach L1 arch piece to the left foot orthotic in the most forward position (or 1 click back).
Attach L2 arch piece to the right foot orthotic 2-3 positions back from the most forward position.
Place both orthodontic insoles into the shoes.
Walk around for 1 minute.
Decide which one feels best and adjust the other one accordingly to match.