(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Urza's Saga gains ": Add ."
II — Urza's Saga gains ", : Create a 0/0 colorless Construct artifact creature token with ‘This creature gets +1/+1 for each artifact you control.'"
III — Search your library for an artifact card with mana cost or , put it onto the battlefield, then shuffle.