how do I network my laptop to my pc?

Ok, so I wasn’t exactly sure how to word this question to do a decent search on google. I kept getting related, but non-specific answers.

My situation is:
I have a laptop, running ubuntu and desktop running the same version of ubuntu.

my desktop is connected, via ethernet, to a netgear router(wireless), which is connected to my internet modem. and that lets my laptop get on the net.

I want to share a folder on my desktop with my laptop. so it’s kind of a wired-to-wireless thing. how do I set that up? I’ve never been good with networking aside from using crossover cables, so I’m not sure how to proceed with this..

thanks 🙂