Activate Clever Conjurer by tapping it, targeting Halo Fountain.
Holding priority, activate Halo Fountain by paying ({W} magic symbol) ({W} magic symbol) , tapping it, and untapping Clever Conjurer and Incubation Druid, causing you to draw a card.
Resolve the Clever Conjurer ability, untapping Halo Fountain.
Repeat.
Once you have drawn your library, you may instead forego activating Incubation Druid's ability to activate Halo Fountain's first ability to create near-infinite 1/1 Citizen creature tokens.