I would recommend a couple of things. First The Lightroom Queen is a great forum and resource -
https://www.lightroomqueen.com/. It is a friendly group like here, and you can ask questions at any level of experience. In fact, most of the questions are from new users, so don't feel shy about joining. Second, there are a lot of good videos about using Lightroom that are free. Julieanne Kost is a great teacher and I generally recommend starting with her videos -
https://www.youtube.com/channel/UCh5bKKSi_bGJh717hVlEbRg. Anthony Morganti also has some helpful videos. Matt Kloskowski helped put on a paid summit earlier this year, and I would look at the instructor list and see what they offer for free. This will also help you get going with respect to the develop module -
https://www.lightroomsummit.com/?r_done=1.
Regarding the monitor, I might suggest to keep it simple and get a monitor that does a good job displaying sRGB (unless you want/need a wide gamut monitor). Wide gamut opens a whole other box of things that you need to understand, and if the goal is web output, the standard is sRGB. If printing is your ultimate goal, then a wide gamut monitor would be helpful, but not essential. The NEC I recommended is a decent monitor. If you are near a Best Buy, you could see what they offer. Otherwise, you will probably be buying on the web. Then again, Costco is offering this from HP -
https://www.costco.com/hp-27"-class-4k-freesync-ips-monitor.product.100664726.html . I do not know anything specific about this monitor, but it is 99% sRGB, 27" and 4k. I've used HP monitors at work (uncalibrated) and have been happy with them, but that is not for anything related to photography.
--Ken