I end up putting mist of it in the trash bin, except glass or metal. It's too hard for me to know which goes what, how am I supposed to know what's compostable

I end up putting mist of it in the trash bin, except glass or metal. It's too hard for me to know which goes what, how am I supposed to know what's compostable (I only have a broad understanding what composting is, and how it's done), much less if this plastic widget that came with the thing is a recyclable one, a compostable one, or made of styrene (which is neither). So off into the trash it goes.