Auto-optimization helps differentiate profitable landing pages and offers that have the best indicators of EPV/EPC in real time and then proceeds to send traffic to those landing pages / offers.
You set up the condition for conversions (required) and Clicks/Time range (optional) -->
These conditions are applied for all offers in the Rule or Path (depends on where you activated it).
So, let's assume you set up 100 conversions per day for all offers. If they reach this number, the system will calculate EPC per each offer and decide which one was better.
The step of optimization is fulfilled and the % of traffic is changed for the next step. If the next day all offers don't reach 100, the step isn't completed and the % of traffic for each offer stays the same. And so on.
You can check optimization logs to see how system works for your offers.