A good website is "shotgunworld.com". The reloading section of their forum is a great resource. I have not checked in there for a number of years, but there used to be some very knowledgeable folks who posted regularly. If you enjoy browsing, you can probably learn most of what you will need to know by reading back through the posts and/ or using their search function. As with any web site - take every tip with a grain of salt. You can generally tell after reading for a while which contributors tend to be reliable.
Shotshell reloading is no more difficult than metallic, but there is less flexibility in substituting components and developing hot loads. The first sign of overpressure can be a kaboom, so every load you use should follow a published recipie exactly, particularly as you get started.
i have two MEC reloaders, & have found them to be extremely reliable and pretty easy to use. It is generally a pain to set most presses up for a different gauge, so folks who reload for different gauges will often have one for each gauge. A club ( trap, skeet, or sporting clays, if you can get to one), is a good source of once fired hulls. There are several large clubs in the Miami/ West Palm area. Their trash cans are usually full of very scroungeable hulls. Stick with one brand to start because of the already mentioned differences in construction, which calls for different wads and crimp setups. I prefer Remington. Their cheapo hulls and premium hulls are basically the same construction, & they all hold up for many reloads.