My side button is on the left. I would like it on the right. How do I do that

See the instructions here

Switch wrists or Digital Crown orientation

If you want to move your Apple Watch to your other wrist or prefer the Digital Crown on the other side, adjust your orientation settings so that raising your wrist wakes your Apple Watch, and turning the Digital Crown moves things in the direction you expect.

1. Open the Settings app on your Apple Watch.
2. Go to General > Orientation.

Change language and orientation on Apple Watch - Apple Support

Are you talking about the phone or the watch?