Seaming aidez

I’ve never seamed and I need to seam this sweater. Anywhere to go to see where I start? HELP PLEASE.

There’s a video here under the Tips section of the Free Videos for matress stitch. It’s a lovely almost invisible way to seam. There are also a few other videos there for seaming (3 needle bind off and kitchener stitch).

The Tips page has a Finishing section towards the bottom which shows a video for mattress stitch