Moments (not the Kodak moments), Centroids & Inertia

That's the first chapter of a book, or the first lecture of a course, on Elementary Theory of Structures!

These have been brought up here before. Did you use the "search all of CR4" function?

I'd recommend reading the Wikipedia articles on these topics first, then reading through the threads here, and then, after having done that, present specific questions here.

Some gross oversimplifications that may help guide your search:

In general, moment is used to mean torque. As you can probably guess, it takes more torque to accelerate a flywheel to a given angular velocity if its weight is a long way from center than to accelerate one with its weight near center. Moment of inertia quantifies this difference. As you can imagine, if you wanted to calculate such a value, you might divide the total mass into a large number of small pieces, and calculate the moment for each piece, and then add it all together. For common shapes, this work has already been done by others... and if you use a CAD system, the system can do it for you.

Centroid means, literally, like a center... so a centroid is the theoretical center of something that might not have an obvious center.

However, the Wikipedia articles are far better than anything I can present here quickly, because they are already extensively hyperlinked, so if there is a term of which you are uncertain, or is of special interest, you can click on it and get more detail or background. Some of the "moment of _____ terms" are often incorrectly used, and the Wikipedia articles, generally, explain the common misuses.

Also, Hyperphysics is very good with this sort of thing, and it is also extensively hyperlinked, so you can start with the basics and progress from there. It is generally more technically accurate than Wikipedia.