Maintenance Schedules in Connection Center
Maintenance mode in SCOM suppresses the generation of alerts that occur on a monitored object. You can find Microsoft's documentation on the subject here. When configured appropriately in a supported system you can schedule Maintenance Mode directly from there. This allows you to more closely tie in your monitoring to your change control processes.
How It Works
Connection Center regularly polls your connection looking for valid maintenance schedules. When it discovers one, it checks the computer referenced and determines if this has a maintenance mode in the correct state. If there is no maintenance mode active it will create a new one matching the settings pulled. If there is a change required and you have allowed Connection Center to update maintenance mode settings it will edit the existing maintenance mode to match the settings pulled. If the settings pulled indicate that the maintenance mode has been canceled and you have allowed Connection Center to cancel maintenance mode the maintenance mode will be stopped.
Connection Center will never apply maintenance mode to computers that are also management servers
Maintenance Schedules in Supported Systems
To see how creation rules work in each of the supported systems please see their dedicated support pages:
Further Reading and Next Steps
For further reading, we would suggest looking at how Maintenance Schedules are handled in the systems themselves via the child pages.
If you have not done so already the next step would be to configure your Inbound Maintenance connection.