Activate Phyrexian Altar sacrificing Jegantha, adding one mana of any color.
Activate Horde of Notions by paying ({W} magic symbol) ({U} magic symbol) ({B} magic symbol) ({R} magic symbol) ({G} magic symbol) , casting Jegantha from your graveyard without paying its mana cost.
Activate Lightning Greaves' equip ability by paying ({0} magic symbol) , attaching it to Jegantha.