Depends on the configuration of your Cisco router and what interfaces it has. There are also IOS version differences to consider. You did not provide enough information to really be able to guide you much in this activity. What models of Cisco gear? What type of gear is your ISP router?
Is this your first time doing any networking? Cisco gear does take some time in getting to understand how it is best configured. It is not just point/click in a GUI. The command line is your friend in configuring Cisco equipment.