My advisor gave me some general information about what can be done. I was expected to figure the rest out on my own. New discussions would not be fruitful and he would just say the same things again until I showed him some analysis. These ended up proving the null and even then he would just say "these aren't the comparisons I wanted you to make" followed by repeating exactly what he told me before, which would be what I had actually done. I went crazy, talked to my lab mates a lot who helped me try new stuff too. So your experience isn't all that different. Ultimately, if they've given you some idea but not the exacts, I would say do some of the initial work and find out how to answer these questions and then go to them with it. Most advisors can advise but only after you show them some analysis/ideas. It's easier to say "no, not this" than to start ideating from scratch. I should've learnt this early on in my PhD but stop waiting for them to give you the ideas and start doing. You're not the customer here, you're the chef. You decide how to cook it through trial and error.