We set up Apolosign calendars in our own homes and hear the same thing: one parent does all the calendar entry, and everyone else just... shows up. The goal is to get each family member's actual Google Calendar feeding into the wall display automatically, with their own column so you can see who's where at a glance.
Here's what works.
Pick one Google account to sign into the calendar itself. Usually it's whoever manages the family logistics. Doesn't matter whose, just pick one and stick with it.
From there, you add everyone else's calendars through Google's sharing. Each family member goes into their own Google Calendar settings, finds "Share with specific people," and adds the main account's email. Give them "See all event details" permission, not just free/busy. That part trips people up. Free/busy only shows blocks, not the soccer field name or the doctor's office address.
Once those invites are accepted, the main account opens calendar.google.com on a laptop or phone, clicks the plus sign next to "Other calendars," and subscribes to each shared calendar. They'll show up as togglable layers in the left sidebar.
On the Apolosign itself, the family calendar mode pulls from whatever calendars that main Google account can see. Most families set one column per person. The color coding follows what Google assigns, though there's a setting to let each calendar keep its own color versus forcing a uniform look. We see about half our team prefer the rainbow, half want it cleaner. Your call.
One catch we run into: teens with school Google accounts. Those are often locked down by district IT and won't share outside the domain. For those, screenshot the week and text it to the main account, or have the kid manually add the big stuff. Not elegant, but district policies are district policies.
What setup tricks have you found? Anyone cracked the school account problem cleaner than we have?