Can someone give me more detail on what this is:
Does this mean that if no VLAN is assigned on a switch status page (under the IP address) then it will assume VLAN 1?
I guess that is a good summary.
It's more important if you are doing things that need a switch management IP address such as 802.1x and RADIUS.
Typically I use VLAN1 for the guest VLAN. Then if you plug in a Meraki device it will be able to connect to the cloud and come online. If it is a switch and you have this configured as the default for switches network wide then after it comes online it will automatically moved to the trusted VLAN, and RADIUS will be able to work.
Or you can set the management VLAN on the uplink of each switch individually or you can set it there like on your screenshot.
It's the VLAN your switch uses to reach the cloud.
so if I change it there, does that mean I can leave this portion below as blank?
If you override it there it will overide the network default management vlan, say no. Once set on the switch you'll need to leave it set.
Correct, the option in the switch settings page counts for every switch unless overridden.
So you could have omitted it from the switches if you had set in in switch settings.