"I have a light blue bonnet on."
Translation:Tha bonaid liath orm.
More or less what this sentence says. There isn't really a word for 'to wear' as in clothes, you have things on you or you put things on you. And oddly the phrase telling someone to wear something is usually 'cosg' which means to spend or to waste, and I have absolutely no idea why you use it for telling someone to put something on.
You have to rethink the English sentence - I have a light blue bonnet on becomes There is a light blue bonnet on me, therefore Tha (there is) bonaid liath (a light blue bonnet/hat) orm (on me) - If you wrote Tha bonaid liath agam that translates directly as There is a light blue bonnet/hat at me, in "real" English, I have a light blue bonnet/hat. So, every time you see I have or I have … on (or any other person as subject, come to that, you have to do that rethink - Tha or Bha or Bidh or whatever tense, then the item, then the appropriate combo word from the orm or agam group - they're listed in the Tips somewhere. Good luck :)