Butterick pattern B4290
Knit fabric in the amount called for by the pattern, plus enough extra to make edging for the collar.
Thread to match the fabric
Iron-on transfer paper
Follow the pattern instructions to make the shirt, using the rounded collar in the pattern.
Use a little of the left over material to create the collar edging.
Find a good Durmstrang logo online and print it off on the transfer paper.
Following the manufacturer's instructions, apply the Durmstrang logo to the front center of the shirt.
© hardhat_cat's tutorial was taken with permission from the Harry Potter Crafts Yahoo! Group.