Shopify New Customer Discount Setup

I need a Shopify expert to set up a 40% discount for new customers. We are not using Shopify Plus.

Requirements:
- Identify new customers by first-time purchase
- Automatic discount application preferred
- Returning customers should automatically receive a 25% discount

Ideal Skills:
- Shopify discount setup experience
- Familiarity with customer segmentation
- Automation tools within Shopify

Please provide examples of similar work and estimated completion time.