The key here is the scope of your question. Say you intend to enter one of those "build a working tricorder" contests. You don't ask "how do I build a tricorder?" That's far too broad, that's asking other people to do your work. You set to working discovering, inventing, tweaking, calibrating, debugging and so on and along the way you discover that when your foobulator gets warm, it gets more flexible and this causes issues for your grabbard. Now you're free to ask (on the appropriate site for each):
- how can I keep a foobulator cool under load?
- is there a way to keep a foobulator rigid even when warm?
- do all grabbards require a rigid substrate?
Or whatever. A very small, very specific question. You don't provide context about working on a tricorder. You don't ask other people to make decisions for you. You ask the information you need to make a decision, whether that's a design decision, how to implement something, or confirming you've discovered something.
On the matter of credit, once you have made your discovery and been rewarded for it, there is nothing wrong with thanking the helpful people of [site] who contributed many small details and facts that were helpful along the way. That doesn't mean you don't deserve full credit for coming up with the questions and making good decisions with the help of the answers.