Distribute ADSL Modem Internet connection via wireless router having LAN WAN port

How to distribute a ADSL Modem Internet connection or BSNL Broadband Internet connection via another Wireless Router/Accesspoint, having LAN WAN port in it. You need a modem (ADSL) having Telephone Line Port (DSL line) and a RJ45 or LAN port in it. Also you need a standard router.