What is a good tutorial for web app UI/UX design?

I’m building a web app, but I’m not a designer, so I rely on a lightweight CSS framework to provide the basic styling and structure of different UI elements. However, I usually struggle with how to structure the web app to provide a good UX.

I googled “web app ux design” (and “ui design”), but most of the results talk about designing a web “site” not a web “app”. For example, the main focus seems to be the principles of design, e.g. color/contrast, visual hierarchy, spacing, etc. What I need are things like general app layout, hub & spoke pattern, navigation, side-bars / menus, relationship between conceptual/data model and pages/screens, role-based functionality, record details vs lists/tables, page sections/layout, cards, in-page actions, form design for simple in-page manipulation vs. complex data entry (multi-step wizards), etc.

Where can I find such a tutorial or guide? I’m willing to even pay for an online course if one is available.