Finishing techniques

I just finished my first baby sweater but am at a loss of how to seam it. I do have a really good book with color pictures and text of different seaming for different parts of a sweater, but I tried all morning and can’t seem to understand how to translate what I am seeing in the pics to what I am actually trying to seam.
I have dial-up modem, so very hard to download any tutorials.
I don’t know if anyone can help me but thought I would ask.

Try this tutorial on mattress stitch at

THanks so much–I will give it a try!