I can not solve this problem.
There modem / router (192.168.1.1) with wifi which distributes online. There wifi and router with dd-wrt, which must also distribute the Internet, but in the subnet 192.168.2.1.
How to configure a router with dd-wrt, that it was possible to connect by cable to the lan port of the first router (192.168.1.1) and when connected to the router on which the dd-wrt on lan or wifi, the device receives from the network ip 192.168.2.X and have access to the internet?
All you should have to do is change the router's LAN address to 192.168.2.1 and adjust the DHCP range and similar parameters to match. All other parameters (other than configuring things you specifically need) can stay at their defaults. Then connect the new router's WAN port to one of the modem/router's LAN ports.