Many of us are about to begin a new semester of online teaching. The learning curve for moving my lecture units last semester was STEEP, so I compiled some sort of hand over notes to people approaching this for the first time. I hope it's useful for someone somewhere.
Reduction in the amount of content was important. What used to be 2 x 1 hr in-person lectures/week had to be condensed down into 6 x 10 minute prerecorded videos (aka aynchronounous content) with 1 x hr live zoom session (synchronous). Even that was too much.
For the sake of yourself and your students, SLASH. Slash your content down. This doesn't mean having to lose important stuff, but keeping it short and sweet.
10 minute video chunks was just about short enough to hold attention. Have you tried watching an online lecture? It is HARD to maintain focus. The shorter the better.
Importantly, each 10 minute video had an explicit Intended Learning Objective given at the end and in the associated text, so that everyone knew what the point was (and how this might relate to assessment later).