Welcome to Catholic Answers Forums, or CAF as we often call it.
Yes, this site is large and at first it can be overwhelming in its complexity. Please be patient and ask any questions you might have. We've all experienced what its like to be new here, so are more than happy to help any way we can.
If you don't mind my saying, I think you've already gotten one of the basic understandings down. And that is how to start a discussion thread! After all, that is what you've done here.
So the matter becomes which of the many forums of CAF is best to ask your question. If you are willing to put your question before the general membership you are likely to get an answer quickly. In fact, you may get many answers, some of which disagree with one anther. Such is the nature of online discussion!
Here is a link to a summary description of the forums here. It is intended to help us decide where to start new discussion threads. In fact, it is called "Choosing Your Forum Wisely."
I'm not sure what exactly your question is, but perhaps the Spirituality forum would be a good fit since it concerns the saints (which, of course, the archangels are.) However, you may also want to ask in Sacred Scripture if the nature of your question is more of a biblical nature.
If however, you don't want your question to be answered by the general membership, you might want to ask the staff apologists of Catholic Answers. This is a bit more difficult because it uses a process unlike the rest of the forums here. What you would need to do is visit the Ask An Apologist forum (often called AAA) and then click on the sub-forum which is titled Ask Your Question Here. The link to that sub-forum is near the top of the AAA forum, but here is a direct link.
Once in the Ask Your Question Here forum, you start a new thread just as you would do anywhere else. However, unlike all the other forums, your thread will not appear publicly. You have to trust that the forum software is working, and that the apologists will receive your question. They will. Your question and their answer will appear in the AAA forum eventually.... if the apologists answer it. Not all questions get answered.
The process of asking questions to the apologists is explained more fully in the rules post. It also tells how to ask questions via telephone or snail mail, two methods guaranteed to get an answer to your question. Here is a link to the rules of AAA
Whew! I just threw a lot of information at you. I hope it wasn't too much and that perhaps some of it helped. And I hope to see you around the forums!
Again, feel free to ask any questions you might have about CAF.