Does someone have a good guide to setting up a remove desktop between two pc's ?

Caveats:
- i'm on the same network
- each computer cannot see each other (They login to the wifi through a web gui)
- I've tried to connect to things via their IP before and it couldn't find the folder
- can only have 5 devices on the network at one time

would like to eventually make this so that my desktop that i'm slowly turning into a media center can host the videos and such for the network [this network problem is only temporary for another few months]