So I've offered you a starting point. You can probably find the book at your local used book store. It's about 600 pages thick, so you can see why I'm not going to start posting it here ( not to mention copyright ). I trust you've already read the classics by Ruppelt, Keyhoe, Edwards, Hynek, Vallee, Klass and Condon.
Also, ( if you haven't already ), take an astronomy course, read-up on meteorology and aviation and start looking up more often when you are outside. Get an idea of what kinds of cloud formations are at what altitudes and how aircraft look from various angles in the day and at night, and what stars, planets, satellites, the moon and metor showers look like. Don't just take it for granted and look at pictures on the internet ... get outside and observe. Check out an air show, do some storm chasing, watch a meteor shower and a lunar eclipse. Last but not least talk to people, and if they are kind enough to tell you their story, try to listen without getting all judgmental. These activities can all be quite enjoyable and educational.
Once you've done all the above and talked in-person with a few dozen people who have stories to tell, then that's your ufology 101.