see the button attached to tab fold it back over itself use pritt stick and iron that in position. Fold over and take your time to Iron it as neat as possible. If you dont do this it looks shite. Also starch the sleeve prior to ironing but dont iron when its wet. On each fold iron it so it looks pristine with tons of steam then dry iron it. Use pritt stick or a bar of soap on the crease on the inside iron it, split it then iron it. Take your time and do it right.
Don't know why you're rolling your sleeves up anyhow. After 1800 is long sleeve order. Well, that's what I've been told. Not worn long sleeves in over 8 years. Think it looks gash but hey ho, I don't make the rules.