To do this, you require a RADIUS server which has the ability to verify against the system which stores your staff credentials. For most enterprises, this will be Microsoft Active Directory.
Many people deploy Microsoft NPS (a free RADIUS server) which is integrated into their Windows Domain. This RADIUS server will receive authentication requests from the Meraki Access Point and perform the lookup against Active Directory.
Although the overall process isn't incredibly difficult, there are a number of changes and configuration steps to reach the end goal. You will have to assess whether it makes sense for your organisation or not.