Configure TP-Link ER605

Does anyone have experience configuring the routing on a TP-Link ER605 router with the Cisco DPC3941B modem in “passthrough” mode with a static ip block? 

I attempted it this morning to no avail. I followed the directions in the forum to set my modem into passthrough mode, had an issue, had to call support. They said something wasn’t set right for passthrough, they fixed it and verified they could ping the gateway.

I set the router WAN to static ip, entered the first address in my block as the IP address, set the subnet to my blocks subnet, set the default gateway to my Comcast gateway and the router said it was connected. From there I tried setting up the routing to route outgoing internet traffic and just couldn’t get it going so I had to back out of it.

This was done using only a laptop connected to the LAN interface of the TP-Link router and the WAN port of the router connected to LAN 1 on the Comcast modem. I disconnected the rest of my network while doing this.

My ultimate goal is to have the TP-Link router controlled by my TP-Link Omada Controller the rest of my network is on. After I get the outbound internet routed, I also need to set up routing for my website(s), etc…, but my primary concern is getting outgoing internet routed correctly.

It’s been a few years since I have had to configure a router in this way, I have been using the Comcast modem settings for my needs but have recently upgraded my LAN and wanted more control over my firewall and better logging, thus the new router. I feel like I am missing something stupidly simple. Any help would be greatly appreciated.

 
Thanx in advance.