I just got two laptops and I wanted to connect them to the same internet service they told me I needed a router one laptop is going to be upstairs and the other one in the basement can I connect them like that? And how do I connect them. I don't know anything about computers so I really need help

The normal connection procedure is to connect the modem (either cable modem or DSL modem) to the router. There is usually one "special" connection made for connecting to the Internet. It might be labeled "Internet" or "WAN" (Wide Area Network) or something similar.

You then connect the computers to the other ports of the router. Use standard Ethernet cables and connect them to the Ethernet ports of the computers.

The Linksys site has a bunch of information on setting up a home network (which is what you're doing):

Linksys® by Cisco » Home

As does the D-Link site:

D-Link | Welcome

And the NetGear site:

NETGEAR - Wireless routers, adapters, and other networking solutions for the home, smb, and broadservice Providers

A typical home router costs about $50