Mike, greetings and welcome to POTN!
Gosh, there is so much ground to cover!
As to "accessories", one thing to look at is the "second kit lens", the EF-S 55-250 IS lens. It will expand your focal length range very nicely and is quite inexpensive. The two "kit" lenses can give you a whole lot of mileage as you are learning and growing in your photography. You'll hear about other lenses, "primes" (fixed focal length lenses) that will give you wider/faster apertures to work with and typically give you a broad range of crisp, sharp images that zooms tend to be a bit weak in, and also high-quality zooms that will cost you, but the two kit lenses will get you started!
Othe major additions to me would be a sturdy tripod and either a cable shutter release or a wireless/remote shutter release for times where you want to capture a scene with optimal sharpness and you don't need a fast shutter speed as much as you need things like a low ISO and a narrow aperture, with the techniques to ensure you can get the shot without camera shake messing up the image.
And then, an external flash such as a Canon SpeedLite can be dramatically helpful when you need a flash but want to avoid the ugly "flash shapshot" look. An external flash can be fastened to your hotshoe and the head tilted up to "bounce" the light, which really helps the look of the flash photo. It also can be removed and triggered by either a cable or a wireless remote trigger or by a "master" flash unit to give more pleasing results.
As to books and such, well, I'll start with two:
David Busch publishes books that cover each Canon model, kind of an "expanded" manual where he delves into the "why and how" much more than the manuals. So, read the manual thoroughly, but I'd pick up the Busch book for your camera and spend some real time in it.
The next book is a "classic", "Understanding Exposure, Third Edition" by Bryan Peterson. Like I said it is a classic, and the most-recommended book here in POTN. It's not a technically complicated book but a good hands-on approach to learning how your camera works. I said Third Edition, because he started writing all this when he was shooting film, so the first and also the second edition have some "blanks" where he hadn't caught up to digital technology. The Third is preferred!
And then, the online community is rich with learning resources!
One thing you can do here in POTN is to spend time in the General Photography Talk sub-forum:
https://photography-on-the.net/forum/forumdisplay.php?f=13
You'll see there are "stickies" there with a lot of helpful info, pointing to books and online resources. But first, take a bit of time to look at this POTN "Newbie Guide", a cool very informative writeup:
https://photography-on-the.net/forum/showthread.php?t=414088
And, spend some time reading the threads that pop up there, and get involved! You can ask questions and discuss things in that sub-forum, and then get ready to go to the Photo Sharing section of something your interested in and post some photos! And each "sharing" section also has a related "Talk" section that you can go to an post questions and discussions about that particular type of photography!
Have fun, and see you in the forums!
- where I would appreciate comments..
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