layer 3 interfaces on your MX and then trunk the required VLANs down to your switches where you would assign them to your edge switchports.
Or, as you have quite a beefy core switch you would probably assign your SVIs on the core, trunk those down to your edge switches and have a routed interface upstream to your MX.
First option may be more suitable if you’re going to block inter vlan routing between certain VLANs using the firewall rules within the MX.
All depends on your design and requirements
Darren OConnor | doconnor@resalire.co.uk
https://www.linkedin.com/in/darrenoconnor/
I'm not an employee of Cisco/Meraki. My posts are based on Meraki best practice and what has worked for me in the field.