How to join raglan seams

Hi just started to knit a cardigan got to neckband and it says join reglan seams please tell me what that means also how do i knit right and front borders, i am using king cole pattern 4287 in the round neck cardigan.

The raglan seams are the gradually sloping decreases toward the upper sleeves, the fronts and the back. This video shows the placement of the sleeve on one side. Since you’re knitting a cardigan, you can join both sleeves, one on each side of the back and then join a front to each sleeve. Lay it out on a table to make sure you’re joining the correct seams.

To pick up stitches for the right and left front use the method of picking up shown here: