Do you have FTP program on your computer such as FileZilla.
If so get the IP number of your box Menu -> Information -> Network -> IP
Your user name will be root
Your password will be the one you set up, or Menu -> setup -> network -> password you can press the text button on your remote to get an easier way on inputting the password.. Paswords are case sensitive.
In FileZilla (or any ftp program)
Host - IP number of your box
Port - can be left blank
Encryption - Use explicit FTP over TLS if available
Login type - normal
User - root
Password - your password
Do you have SAMBA enabled on the box?
Menu ->setup ->network> utilities -> samba
If so look in the Network section of Fie Explorer on your PC