Theoretically:
- Turn off WiFi on C6300
- Connect LAN port from C6300 to WAN port on S1300
2a. Make sure that the C6300 is on different IP subnet ( should be as it looks like it defaults to 192.168.1.1 and your S1300 should be 192.168.8.1) - This should give you internet to the S1300 and WiFi via the S1300
- For Mesh have a look here (same as B1300). Only the master node needs to be hooked up to the internet.