on that router (to prevent a conflict with the first router)-- keep it in the same IP range, then in the configuration page of the router you will see a choices of use 'as access point' or 'as expander'... OR a choices of connect to ISP or connect to another wireless network.

I think, you also have to disable the dhcp.

You have to use the same SSID name and password.

Disable security while configuring, to prevent any difficulty/confusion.

Read the manual for more detail information.