When you first power on DDR Konamix, you will be able to select 32 songs. 20 additional songs are hidden and must be unlocked by playing Game Mode or Solo Mode. For every 5 songs you clear (failures don't count) in either mode, a song will be unlocked. This will continue until you're up to the maximum of 52.
If that is not what you are lookin' for Red PM me and I will hook ya up with some more info.