I'm trying to add more example sentences, but it takes time because I run them all by native speakers before they appear on these pages.

I can help you out with that usage though. Like the point says, it's often used when making decisions, like at a restaurant. If the waiter asks you what you want, you could say
カレーにします. (I'll have the curry).

The adjectival forms are much rarer, but still valid. The noun form is what I hear the most often.