Activate Terra, Magical Adept by paying 4 and tapping it, exiling it and returning it to the battlefield as Esper Terra.
When Esper Terra enters the battlefield with four lore counters on it due to Doubling Season and Winding Constrictor, its fourth chapter ability triggers, causing you to add , and then exile Esper Terra and return it to the battlefield as Terra, Magical Adept.
When Terra, Magical Adept enters the battlefield, it triggers, causing you to mill five cards and return up to one enchantment card from among them from your graveyard to your hand.
Repeat.
This intricate loop begins by tapping Terra, Magical Adept to transform it into Esper Terra, which immediately enters the battlefield primed for acceleration. Thanks to Doubling Season doubling the incoming lore counters and Winding Constrictor adding an extra one for good measure, Esper Terra arrives with a staggering four counters, instantly triggering its final chapter. This fourth ability floods your mana pool with ten colored mana and cycles Esper Terra right back to its front face, triggering Terra, Magical Adept to mill five cards and potentially reclaim an enchantment from your graveyard. Because you are left with plenty of mana leftover from the transformation, you can simply pay the activation cost to repeat the entire cycle, generating infinite mana, self-mill, and continuous enter-the-battlefield triggers.