Most routers come with a CD with a wizard that guides you thru the process. Have you tried that.
Otherwise manually is really no problem so long as you follow the instruction in the quick start leaflet or download the manual and read that .
I've found the main rules are:
a) always set the router up using a cable between computer and router.
b) get the computer talking to the router first before you worry about the internet connection. Once you get to the ISP setup parts, go to the ISP's support website and look for a help file on setting up popular router models to work with their service. If not, ring the ISP helpline and get them to walk you through setting up the connection between router's WAN side and the ISP.
c) always troubleshoot with wireless security turned off.
d) On a DSL setup (phone line type internet) don't forget to put filters on.