Alexandrian Wicca is one of the branches of British Traditional Wicca. BTW includes such Traditions as Gardnerian, Alexandrian, Kingstone, Silver Crescent, etc. All of these Traditions include an initiatory lineage tracing back to Gerald Gardner and the New Forest Coven. All are oath-bound mystery Traditions.
If you wish to become Alexandrian you must find a proper Alexandrian coven to train with and into which to become initiated. There is no way to teach yourself how to be Alexandrian, and without the proper training and initiation you would not be considered Alexandrian. Initiation by someone who is a legitimate Alexandrian Wiccan is absolutely essential if one is to become an Alexandrian.
If you are looking for some books that will talk about the Outer Court (public information) about Alexandrian Wicca then the books by Janet and Stewart Farrar are helpful. (But not the books by Janet Farrar and Gavin Bone). I would also suggest reading the books by Gerald Gardner to whom Alexandrian Wicca traces its beginning. However, understand that what actually teaches on about Alexandrian Wicca is the oral lore shared only between initiator and initiate.
I know that it has been suggested that you access the so-called "Alexandrian BOS" is available on-line. As I have said, the writings in that BOS are oath-bound and only made available once one has already been initiated. So I would doubt the validity of any supposed copy of any BOS from any of the Traditions of British Traditional Wicca.
I will also note, since your profile does not indicate your age, that no BTW coven will accept for training anyone under the age of 21.
While I am not Alexandrian, I am a 3rd Degree Gardnerian priestess, and I would be happy to try to answer any questions you have about BTW Trads, at least as so far as my oaths permit.