Lay out your work flat, right side up, neck to neck, with the sleeves coming out the sides. You are going to sew the diagonal lines connecting the sleeves to the front and back--both sides of the left sleeve and only the front of the right sleeve. This will allow you to put your work on the needles to work the collar back and forth.
Hildie's right--use mattress stitch for these seams--it is amazing how nicely it works for raglan.
I couldn't get in to see the pattern on my computer here at work, but this is the way that raglans generally go together. The top stitches of the front, back and sleeves get connected as you make the collar. There aren't any shoulder seams to speak of.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry