Thanks for the tutorial...
But let me add this...
If your secondary router is on the higher-end side and much better than your ISP's stock modem, then you just need to set your ISP's stock modem to bridge mode, turn off its DHCP and WiFi broadcast, and let your secondary high-end router handle all those work. In this way, mababawasan ang cpu at ram load ng stock ISP modem dahil medyo nasa low-end lang kasi ang mga modem ng ISP eh, so malaking kabawasan un sa usage ng stock ISP modem dahil ang dating ginagawa ng stock ISP modem ay tatrabahuin na ng secondary high-end router mo.