home server/network questions

I am not a n00b from the aspect of running Linux on a desktop but on a server or networking two machines I am a total n00b. I have three machines, two Linux laptops and one desktop, one wireless router, and two external hard drives. I want to share the files on the external hard drives over my network with the two laptops. I am thinking I could share over my wireless network the external hard drives by connecting them to the desktop machine and having that desktop function as a NFS or sshfs server with that desktop connected to my wireless router. I think all of this is possible but I have no idea where to start and how to not open up my network to attacks. Any advice or links Would be helpful.