how to use こと and もの

[Jdzspace9765]

I have been scouring the internet to try to understand how to use these words. I know that koto is for things you can touch, and mono is for things you can't touch.

I even found that they are used for "recollection" , "emotion" and "of course"

but it's not making much sense to me. I understand using the words by themselves. But from watching TV shows and reading things I see mono and koto used all the time. For example, Kaimono= shopping.

I understand buy+thing= shop. But there are other words I've seen in text that feel like they mean the same thing without koto or mono added on, but when i talk to my japanese friends they tell me it has to have koto or mono attached.

but they can't really explain why, or what the rule is. and from what i've found online, it's not something a lot of people really talk about either. Maybe it's me.....I don't know. So I thought I would ask the community, to see if someone can help me get a grasp on this concept.

thanks in advance