Help with running internet

Hi

I have a Wireless Laptop upstairs away from my router, and I want to run the internet from the laptop to a desktop right next to the laptop. I would like to do this without use of a router, but I don’t have a clue. I have ethernet cables and I have network cards in both computers. Hope you can help. I have tried to enable internet sharing and plug a ethernet cord into both computers. Thanks for your tips.