Briefcases are used for syncing files between computers, i havn't actually used them, and i don't care much to read up how they work, if you want to know more, take a look at this link >> >>
Sync using Briefcase
The best place to create many folders? It really doesn't matter, folders are made so they could be placed anywhere, they suite everyones different needs for organization. Make them where ever your heart desires, if you wish, put them in the Windows folder, LOL.
If you want your files tucked away, put them in My documents, if you wish to quickly access them, Put them on your desktop. If you have a Project, make a folder for it and put everything you need nice and organized in there, but there is really no "Best Place" to create folders. just make sure you defragment your HD about every month and check your computer for virus's at about the same time

thats the best i can tell you
