How can I share my laptops wifi with a wired desktop by ethernet

I'm guessing this is really easy to do but i tried and it didn't work. I have a desktop running Mint 20 and a laptop running Mint 19, I think. I don't have a wifi card in the desktop so it needs to be plugged in to the router. I don't want to be running ethernet cables all over the house so I was wondering if I can plug the desktop into the laptop with an ethernet cable and use the wifi that way. It's not a permanent solution but I don't want the desktop plugged into internet all the time anyway, just the odd time and I can bring the laptop over to it.

Like I said I did try by plugging the cable in and the desktop did try to connect but it failed unfortunately. I'd say I need to give it permission or something. Anyway thanks in advance!