The Complete Perplexity AI Guide for 2026 Perplexity processed 780M queries in May 2025. The complete 2026 guide: learn how it works, Free vs Pro, Deep Research, Spaces, and expert tips for power users. April 27, 2026 • Shann Holmberg perplexity ai perplexity guide 2026 how to use perplexity ai perplexity deep research ai search engine