Hi,
If you just need WPA2-Enterprise using clearpass policy manager with meraki then it is pretty simple.
For Meraki you need to go to Wireless-> Configure -> SSID.
Create a new SSID or edit an existing one.
Under "Network Access" select Enterprise and in the dropdown box next to it, select "My radius server".
Then scroll down and you'll see "radius server". Just add the clearpass server, port 1812 and your shared secret.
In clearpass just create a generic 802.1x wireless policy.
Just be aware that your radius requests will come from each Meraki AP. So you need to add all the AP's as a radius device in clearpass. Or use a subnet. All AP's should have access to the clearpass appliance at port 1812. The vendor code you need to select is Cisco.
If you want more details, I can check the configuration I have running with customer tomorrow.