hreflang Plan (Multi-Language/Region)

Help me set up hreflang for my multi-language/region site. LANGUAGES & REGIONS: [[LANGUAGES_REGIONS]] URL STRUCTURE: [[URL_STRUCTURE]] (subfolders, subdomains, ccTLDs) PLATFORM: [[PLATFORM]] Deliver: 1. The right hreflang setup for my structure (with examples) 2. x-default handling 3. Common hreflang mistakes (missing return tags, wrong codes) and how to avoid them 4. How it interacts with canonical tags 5. How to validate it Give me copy-paste examples for my exact case.Copy