DJ Conway isn't the best source because she makes stuff up [and I read Dances with Dragons, there was maybe one chapters worth of information. Everything else was pure fluffy nonsense imo anyway] sadly she is credited as the founder of Dragon Magick. You cannot summon a physical Dragon, nor can you control a Dragon. Dragons are seen similar to angels, demons, or fae, you work with them.
Little is written because A. it's passed verbally from the dragons to you [and again, they are ASTRAL they are not physical] and B. many clans [covens] typically have a code against revealing information to those who haven't been proven trustworthy.
Best to look into astral projection and speaking with them directly. They aren't evil, a little intimidating but if you wish to learn so you can grow on your path they will more than likely teach you.
Couple things though:
You cannot become a Dragon, nor can you gain their powers or grow wings/tail/scales/claws like a Dragon.
Dragons take things seriously as well as literally. Treating things as a joke, or wording something wrong will end badly for you.
Every path is different. They will teach you what you need to know now, so don't argue you want to learn [example] spell casting when they want you to learn about chakras. There's a reason.