How to set in raglan sleeves?


I have been knitting a little bolero for my daughter. I´m all done with knitting the pieces but I have no idea how to sew the sleeves to the back and the front parts of the bolero. I have made other knitted sweaters with out problems but this is my first raglan piece. When I finished making the front piece it ended with only one stitch to cast off and the sleeves ended with 15 stitches to cast off. Is the 15 stitch cast off row of the sleeve supposed to be a part of the neckband??
Any help would be very much appreciated.

Bye bye

Pin the pieces together like they will be sewn, which you would want to use mattress stitch to do. Don’t worry that you have more on the sleeves than the front, it’s probably how that pattern is written. You probably will be picking up sts around the neck for a neckband and it will all come together.

Thank you so much.
I thought that the pieces looked a bit strange when I was done knitting them and was afraid to mess everything up by sewing them together incorrectly.
Thank yo so much again
I very much appreciate your help:)