This is a deck I used a while back. You basically need to get your Dark Magician out from your deck and use your Spells and Traps, like
Dark Magical Circle and
Eternal Soul to help you bring more Spellcaster monsters to your hand/field. Use
Magicalize Fusion when you're ready to Fusion Summon any monster, and
Burial From A Different Dimension will bring them back to your graveyard, allowing you to Fusion Summon more.