https://blogs.vmware.com/opensource/2022/01/11/5-things-you-should-know-before-getting-into-open-source/

As expected of a proprietary company this is mostly missing the important points.

How to get into contributing to open-source / libre projects? (note: there isn't just source code)

Scratch your own itches, make the changes you want to see or point them out. People can provide some help and documentation but they're not your manager/boss, they're not gonna point tasks at your without being familiar with you.

Don't hesitate to talk to project members before sending your changes, they might have better ideas or specifically want theirs and sometimes it's more worth it to let other people make the fix as it might not be where you expect it (ie. library or even into a standard).

Not everyone should learn the same tool/implementation, try some of them, pick the one you feel is the best, text editor choices tend to be quite personal.
Not everyone uses git, and even within git, not everyone uses the PR workflow, don't expect it everywhere.