I hate missing school. It's stressful. I have to do multiple days worth of planning ahead of time, plus know what's happening the day I get back. Then, I have to turn those plans into a written document that anyone in the world can follow to the letter.
I still leave a document with some specific notes for a substitute - things like management or specifics to take note of. But now, instead of writing out a ton of information on what to do, I record a simple video and post it to a static page on my class website. There are a couple little tricks I learned along the way:
1. The page should be bare bones. Don't worry about making it "feel" like the rest of your class site. It should be something easy to display on a projector without having to hunt through menus to get the information. That also allows you to just replace the video and written instructions for the next time you're out. Flexibility is key.
2. Embed the video right in that page. If you're like me, you want to make sure that video is responsive, too. I found a super-handy little snippet of CSS to make YouTube videos responsive, and I used that so students can access the information on their own later on any platform.
3. Keep your video unlisted so it stays within context. I have a lot of content on YouTube, I want to keep the sub plans isolated because they don't really fit in the flow of anything else there. This way, the video only "exists" when student need it - while I'm gone.