FTP naming????

I want to rename the file on my FTP that consists all my WordPress files (currently called wordpress-4).

my site : http://www.discoverartwork.com/wordpress-4

I want the link to be: http://www.discoverartwork.com/shop

But when I change the file on the FTP to “shop” for example every time I go to a new page I get an error message is there an easy way of doing this or will I have to start a fresh???

Thanks WordPress… 🙂