It's not that you didn't know about the meeting. It's on your calendar. But "meeting at 2" didn't trigger "start preparing at 1:50." You were deep in something else, and now you're joining late, unmuted, with no idea what the agenda is. A backward plan makes the prep automatic.
You start "getting ready" for a Zoom call when the calendar notification fires, usually 1 minute before. If you lose track of time easily, that minute isn't enough. You need to find the link (is it in email? Slack? the calendar invite?), fill your water, use the bathroom, and at least glance at the agenda. That's 10 minutes of prep you consistently don't have.
Ready Time turns meeting prep into a short sequence starting 15 minutes before the call. Bathroom and water. Find and test the meeting link. Review the agenda and your notes. Open any docs you'll need. When the call starts, you're already there. Camera on, muted, caught up.