Shaping R & L front of cardigan edges?

Please help! I am still a novice knitter…cardigan has no buttons,
and a Band bordering down both sides of the R & L front pieces.

Went great with the first ® front. Then the pattern stated for the opposite front shaping, for me to “reverse” what was done on the first ® front ?

This shaping makes the gradual “curve” of the garment as it lies across the chest.

WHAT AM I SUPPOSE TO DO to get this shaping on the “left side” now??

Thank You

The opposite of what you did on the right side.

If it said,
Dec every 3rd row on the right edge you would dec every 3rd row on the left edge.
If it said
Dec every 3rd row at the end of the row you would dec every 3rd row at the beginning of the row.

You just put the shaping on the opposite edge from the first piece. Thin might include binding off on the WS because you can’t BO at the end of a row, only the beginning of one.