Hi Arthur,
I'm not the most technically adept either, but here goes:
Once you've run the wireless set up wizard on both machines, you should, at some point, enter the WEP, or preferably WPA (more secure) password into both machines, which should then save the connection set up on the laptop, and you shouldn't have to enter it again, all the time you are using the same connection at home.
As for folder / file sharing, you have to make sure File and Printer Sharing is enabled on both machines (I think it should have given you the option in the connection set up wizard). When you have created the folder you wish to share, in XP, right click it, select Sharing and Security, then tick the box to 'Share this folder on the network'. Hopefully that should do it. Oh, and you have to make sure File and Printer Sharing is allowed through your software firewall too.
If I haven't made it clear, or said something wrong, please come back to us.