I known that the location of Mada is in the lower dungeons...but how does one get there???

Welcome to the board, Ckone1167!!!

Well - the Lich has to give you the key which will open the gate to the lower dungeons (the entrance to this area is almost directly below the entrance to Skull Castle).

Once down there, you have to deal with a bridge/lift puzzle (don't make it more complicated than it is! Look out the window when you are flipping levers and see which sections of the bridge raise or lower. You will have to jump some sections but you shouldn't ever have to go back and set levers from a previous area to solve this puzzle.)

Mada is in the western section behind a door next to which are what look like skull reliefs - use the staff to open the door!

Good Luck, Wyv