Connect to http://wired.meraki.com/#configure on a PC/Server connect to the meraki. The default username is the serial number of the device which can be got from the Cloud Dashboard and password is blank

The following will restart the Meraki so make sure you arrange downtime.

Change Port 2 to Internet from LAN and add the IP details and click Save

Make sure all ethernets are set to Auto for Negotiation

By default the Meraki will put the connections on Active / Passive , to enable Active / Active 

Login to your Meraki Cloud Dashboard and Enable Load Balancing : 

This will spread both inbound and outbound via both links

To force one port e.g. to a specific Link , add an Internet Traffic Flow setting

e.g.