Like I said before, this site is a lot like a book. However, you won't have to read everything in strict order. However, you really need to read much of this unit (A-1/Intro and Legal) as well as A-2/Neurobiology basics before going anywhere else. They aren't as dry as they may seem at first glance (save of course, for my sense of humor!). If you don't read at least unit A-2, I promise you'll be more than a bit confused.
Please also note that the whole site isn't up yet. Heck, it may never be entirely up... it might just be a continuously expanding reference! Nonetheless, I intend to ASAP include comprehensive discussions on the more common medications used for neurological and psychiatric disorders.
Now, if there's other stuff you need to read in specific order, you may see a "make sure to read..." bar atop the page. For example, to read about anticonvulsants (a class of drugs used in the treatment of epilepsy as well as bipolar disorder), you'll need to know a good bit about ion channels and the neurotransmitter GABA. Without reading the aforementioned, my section on anticonvulsants will make little-to-no sense whatsoever. (And I mean less sense than the rest of my writing!)
The digestible section on basic neurobiology is key to all of the science discussed here, which is why you'll see it on every page's right-hand menu.
