Here are some recommendations worth revisiting on how to take effective notes, including tips on using the Zettlekasten system.
When attending lectures, online or offline, it is important to recognise there's 3 phases of learning with lectures: before the lecture, during the lecture and after the lecture. Effective notetaking plays a role in all three roles. The University of British Columbia agrees with these tips. And my personal methods are detailed as well.
I make heavy use of the Zettelkasten Method. Basically, It's a method of capturing atomic notes of fairly constrained subject matter, kind of like a Wikipedia article. Also like a Wikipedia article it includes hypertext linking to connect topics. This creates highly relational notes that are easy to search, review, read, and automate. This is thanks to their links, tags and software tools that can automate it.
Don't worry too much about atomicity of notes initially. If a topic is being written about in a larger parent subject of a note, keep it there. You can come back later and strip out the topic into a seperate note document. A good rule of thumb is to split a topic out from a parent topic if you have more than three headers.