Like two or three weeks for most tasks. I still check the manual sometimes, it’s built in :)
Check out vimtutor if you wanna learn it fast
https://vimschool.netlify.app/introduction/vimtutor/
I oft reference the wikibooks page as well https://en.wikibooks.org/wiki/Vim




I get the idea this is meant for Autodidacts who need to try and fail to learn, not for people who are willing to pick up a textbook and just learn the material.
I agree though, the tasks are easy. I get the idea they’re sorted by tedium, not difficulty.