Start with the tutorials and courses in Webflow University. They do a great job of succintly organizing and explaining the basics of every feature in the Webflow UI.
In this course, I'll add some basic notes about the things that confused me, or that were important points of understanding.
Find sites with designs you like, and recreate them in Webflow.
This is called copywork, and has origins at least as far back as Leonardo da Vinci. You learn a lot of technique skills doing copywork, but more importantly, you learn from inside the artist's mind.
In that process, you'll discover what decisions you'd make, and why... and you'll discover your own style in that journey.
The Webflow University has a ton of great resources and will be your primary reference for learning the Webflow environment.
Start with the Webflow 101 Crash Course.
Then explore other courses.
https://www.youtube.com/watch?v=vvyPj5bTcgQ
Dig into hundreds of videos and articles to help you learn Webflow, web design, web development, and much more.