I’m new to Obsidian; where the heck do I start?
By reading the docs.
@visualmapper: Alternatively you can open the help file by pressing F1 in Obsidian. With @WhiteNoise 's method the help texts might be a bit more up-to-date (not sure about that). With F1 you open a local version of the help. So you can change the help files to try things out. You shouldn’t make changes you want to keep though: your changes are resetted automatically at some point.
Next to the help/docs, I also enjoyed this youtube tutorial, to get to know a basic starting workflow (there are plenty more if you don’t like this one).