I just set up directories and subdirectories using Windows Explorer and my own little system for organizing things. I organize things by subject type, nature, scenic, people, etc, then build sub directories based on type and date. It works for me but your mileage may vary. Whatever system that makes sense to you is what you should use.
As for Lightroom, I downloaded the 30 trial a couple of months ago on a lark and to be honest I was not impressed. I removed it from my computer after about a week of fiddling with it. PS5 allows me to do so much more than Lightroom that I could not see spending any more money on a graphics program.