well, the bargue plates are helpful, but it depends on what you want to do. Do you want to draw portraits and figures in a traditional sense then yes they are very helpful and are a great way to start. However, if you wanna be an animator, concept artist, or do anything like that then I would suggest on some other books. I recommend Steve Huston's book , wonderful artist, a great teacher, and taught at many studios. Loomis books are good but their look or design seems outdated, still have much valuable knowledge but I would not recommend starting out with that. Also look around for artists/ teachers on youtube, or courses. Decent guide to knowing wtf the fundamentals are
I recommend Proko's Youtube channel,
Drawabox is also very good drawing channel
The Practice and Science of Drawing (Fully Illustrated and Formatted for Kindle) https://www.amazon.com/dp/B003WMA7DS/ref=cm_sw_r_cp_api_Qojbzb7RESEXZ
I would say Harold speed also pretty inspirational, but it actually looks like she almost copied him word for word on some parts.
I'd say there is probably a book out there for anything you're striving for. Fantasy watercolor art, figurative watercolor, urban watercolor, so you should go for one that is covering the subject you like most! I'm a fantasy lover myself and I'm a big fan of the books by Stephanie Pui-Mun Law, I have 3 of them and they all begin with basic tools, and techniques before getting into painting full works. Good Luck!