The last time someone asked HN where to learn UX/Design was 10 years ago - https://news.ycombinator.com/item?id=1768358, what are some good teach-yourself resources out there today?
Do research, find common patterns.
Use any tool of your liking to design, for example Sketch, Figma are quick to learn and quite popular.
Affinity Design is one of my favourites, for illustration, design, etc.
Read about colour basics, the colour wheel, etc. Contrast, etc. Use www.coolors.co
Read about typography, the most basics.
Keep researching and prototyping.