Order of Whiteclay does not have summoning sickness.
You have a creature card in your graveyard with mana value 3 or less.
({1} magic symbol) available.
Steps
Activate Order of Whiteclay by tapping it, adding ({W} magic symbol) ({W} magic symbol) .
Activate Order of Whiteclay by paying ({1} magic symbol) ({W} magic symbol) ({W} magic symbol) and untapping it, returning a creature card with mana value three or less from your graveyard to the battlefield.
Activate Ashnod's Altar by sacrificing the creature, adding ({C} magic symbol) ({C} magic symbol) .