public IP and private IP set up

Hi,
Forgive me for asking basic question. I don’t know where to ask.

I have a public IP Address from the ISP. In fact 16 IP addresses.
Also there is WAN IP address given by ISP, one for ISP and one for me.

I have a Cisco 877 Router.

I tried to set up one Linux server (172.17.8.24) to use one public IP.
I can’t manage to do it.

Please help me in directing answer or point to the resources.

rgds,