There are no such things as "stupid" questions. However if you think your question is a bit stupid, then this is the right place for you to post it. Please stick to easy to-the-point questions that you feel people can answer fast. For long and complicated questions prefer the other forums within the support section. Before you post please read this
did you share the folder using samba or nfs?? (I use samba so I can access my xp machine.) does he have the same installed?? if he's using celena or daryna it should be as easy as looking in his network folder located in his home folder!! (provided your network is in order)
sorry I couldn't help with nfs but, if you decide to give samba a try it's really easy. just go into administration, then into shared folders and select your shared folder's properties. instead of selecting nfs select smb. under the general properties tab, name your workgroup on both computers the same name. you should then be able to access your shared folder on your friends computer in his network folder (/home/hisname/Network) and vise versa if he shares a folder with you.