Location 1, on same subnet as isp router, different ip, out of dhcp pool, start with ch. 153, set AP mode, MAXTream disable
Location 2 too on same subnet, different ip and out of dhcp pool, same channel, start with ch. 153 Client mode
You can set any ch. you wish, 153 is a suggestion, on that ch. you can test internet connecting from any smartphone 5ghz like iPhone 5 & up, directly to AP, that way you ensure part #1 is ok
Do not connect Lan cable coming from #2 Client to router, test the link connecting to a Desktop, once you have Internet, set that router as AP, disable DHCP, and set ip on same subnet as the others, dif ip out of dhcp from isp router pool, and connect to any of the 4 Ethernet ports, not to WAN
But if you insist on having a router at the end, this must be on a dif subnet from the rest of the network, e.g. let's say ISP router Gateway is 192.168.1.1 that last router must be set to 192.168.2.1, but again, having a second router at the end it's a mistake, the network will be doing double NAT
Once you have the link working its up to you to enable MAXTream
You have double thread, erase the other one