The bounty of books, websites, and discussion forums giving advice about anchor building can be pretty overwhelming.
What's a good place for a new climber to start learning this vital skill?
I've been teaching anchor building classes for about 15 years, and have looked at hundreds of different sources. Here's one that I think is just about the best place for a new climber to begin.
It's one long webpage from the American Alpine Club, and it covers just about every aspect of single pitch / downward pull anchors you could ever want. Yes, some people might nitpick a few of the things on here, but it's the best one page summary on the web I've ever seen. (Darn it, kinda wish I wrote this myself . . .)
This site does not have any discussion of multi directional anchors, which are typically used when you are doing multi pitch climbing. The anchors shown are designed for single pitch climbing or rappelling, when all of the pull comes in a downward (or possibly a bit sideways) direction.
It also assumes that you know the very basics about what sliding X is, and how to tie a cordelette, and a few things like that. If you already know this, then dive into this webpage. If you don't, check out the alpinesavvy video section to learn these fundamentals, and then come back.