1. cut off the sleeves
2. Cut up the side of the tee
3. make the front and back of the tee two rectangles, about mine were 22.5 high x the width of the tee
4. cut the sleeves at the seam, and cut off about and inch at the top to make it more like a rectangle
5. measure child's arm, add that measurement plus an inch - cut elastic to size (my elastic length was 8.5-9")
6. thread elastic through sleeve hem, and sew on both sides.
7. take shirt body front and pin -n-sew a sleeve to the left side at the top right sides together, with the elastic edge facing the bottom----do the same to the back
8. flip the front on to the back so their right sides together. the sleeves you just sewed on will now be the oppisite sides of each other. sew them to the front and back, you'll now have your sleeves attached to the body.
9. clip the seam allowance just after the hem on the sleeve (this is for when you sew the sides together)
10. put a hem around the neckline, big enough for ur elastic, leaving a space to insert it.
11. take ur child's chest measurement, thats how much elastic u need to cut for the neckline
12. string the elastic through the neckline hem, and sew together. close the hem on the neckline.
13. now sew up the sides, to the clip u made at the sleeves.
14. ur now done. Put it on ur girl, they'll be happy.
Hope this is clear.