I believe you can attach them in the item menu if you have both the bombs and the arrows. There should be an option when you click on the bombs I think.
Ok I know this is gonna sound dumb to most of you but I got TP a while ago and stopped playing. I just picked it up again last night to find that I left off in the City in the Sky. For some reason I am having trouble using the spinner in the cogs to extend the first bridge. I hover over it and...