I've been using the official stuff from their site mostly. It's a little dry, but they cover the features pretty well.
I would say if you're starting from zero, spend some time on Master Pages and Styles, then think about what else you need to focus on.
I spent some time at the start getting that stuff set up, and I'm glad I did. I wish I'd done more. For instance I set up the colour swatches for all the repeated colours today, and it saved me time today I'd been wasting previously.
I have a list of things I need to learn that is growing, not shrinking. Each time I learn something it reveals my ignorance of a ton more.
Happy to answer more Qs if you have them.