Hey @Shylock19, for a free learning resource to study brand identity design, you could check out Baseline - it’s a free mini design course that starts with the foundations of design and then delves into various areas of design, including brand identity - you could skip to the area(s) of interest within the course.
For paid learning options, I recommend checking out:
Brand Identity Course by James Martin
The Briefbox Design Course
Become a Brand Master Branding Course by Jacob Cass
Graphic Design Course by ilovecreatives Studio
In terms of design book recommendations, one that comes highly recommended in the design community is Designing Brand Identity: A Comprehensive Guide to the World of Brands and Branding 6th Edition by Alina Wheeler and Rob Meyerson. I’ve yet to read this one, but have it pinned to my Pinterest moodboard so I can get it one day. If interested, you can take a look at the books in my Pinterest moodbard - I’m sure there’s books there that’ll spark your interest.
Also, I recommend learning from specific designers that focus on brand identity - they often offer their own course(s) and/or tutorials related to brand identity design.
Here are several designers I recommend following:
James Martin (madebyjames)
Will Paterson
Thomas Cargill (satori graphics)
James Barnard
Abi Connick
Hope this helps!