Questions regarding the usage of Kto, Co, Kogo

I'm very confused about how the questions kto co etc are supposed to help determine which case it is. Can you use the same verb with say co and kogo? or are there specific verbs for each case that you can only use with that case.

Just finding it hard to get my head around how these questions can help determine the case

they won't - they are a help for Poles learning grammar who know the logic of the languge - they are of no help for the foreigners like yourself - you have to learn when to use which case in other ways

Okay thanks, to be honest, I'm kind of relieved. They are just more confusing to me than anything!

For Polish person - you think the question it answers - you know what the case it is
For foreigner learning Polish - you want to ask a question - you think what case the answer will be- you ask question.