readme: document relative path-based links

Author: ondrejbudai

README.md

@@ -23,3 +23,19 @@ $ make build
 ```
 
 This command generates static content into the `build` directory and can be served using any static contents hosting service.
+
+### Guidelines
+
+When using relative links, please make sure they are path-based, and not URL-based.
+
+❌ Bad:
+```markdown
+[Blueprint](../overview/blueprint)
+```
+
+✅ Good:
+```markdown
+[Blueprint](../01-overview/blueprint.md)
+```
+
+This follows Docusaurus' guidance, see [their docs](https://docusaurus.io/docs/markdown-features/links) for more information.