I’m sort of self taught with most UX stuff, weirdly enough. When I was in undergrad, design was considered to be both aesthetic and functional, so we were always encouraged to view design as a problem solving exercise and “solve the brief” (not just make something pretty). Because I was trained this way I think it helped me transition into UX-thinking easier.
Regarding some of the more specific questions:
eCommerce has largely been ‘solved’; look closely at other online stores and see how they do things. You’ll quickly see a pattern emerge.
For the shopping experience: most of the time you’re going to see a cart in the top right navbar, a large and prominent ‘add to cart’ button on product pages, and some kind of animation or feedback that indicates when you’ve added something to the cart.
For the checkout process, there’s usually a few common parts-- order review, add coupons/promo codes, payment info, shipping info, and ‘thank you’. There may have some other unique info requests for the user, but rarely.
I like to look at sites like https://www.siteinspire.com/ or https://www.awwwards.com/ for ideas. Some of these are very industry-specific though, so keep your target audience in mind while browsing. If your site is aimed at the elderly, for example, a cutting edge navigation scheme may just be confusing for them.
Also, I don’t have any books to offer, but I’ll always recommend sketching on paper with a pencil before you do anything in ‘high fidelity’ in Photoshop or in code. Make lists of your requirements and see how many you can meet designing on paper. Paper is loose enough that you can move fast and discover new solutions quickly. You’re also less likely to become super attached to a paper sketch, so you can keep iterating easily.