It's a pretty advanced library, and I don't think you should use it if you've only been trying Haskell for a few weeks. I've been using Haskell for about 7 years, 5 of which commerically, and I've never used it seriously. I find the smaller lens libraries, like 'fclabels', solve the most important problems 'lens' also solves, but with a lot less surface area and complexity. But even that can wait until you're further along.