Hi!
OpenStreetMap is a map that anyone can edit and anyone can freely reuse. It has a huge ecosystem, and can thus be a bit confusing to edit or to work with.
I thought that having a weekly thread to ask all beginner questions would be nice for everyone interested, so - go for it!
If you know the answer to a question, please answer (so that I don’t have to answer everything).
Whelp, this is the beginners-question chat! This is already quite advanced what you are doing there!
You will find more information on the wiki page on sidewalks and the crossings page. However, there is no consensus on how to do it. Some map it as discrete way (but this is a lot of work, duplicates some data such as streetnames), others map it as tag on the road. Both approaches have advantages and drawbacks; for some real-life situations it makes sense to do it one way and it others the other makes a lot of sense. And there is a grey area where neither approach is a good fit…
Not to mention that this is done differently in some countries due to OSM-tradition, different legal implications or forms of the sidewalk… So, good luck with this journey!