fix: typo

docs/index.md

@@ -9,7 +9,7 @@ in the [Diátaxis documentation framework](https://diataxis.fr/)
 and consists of four separate parts:
 
 1. [Tutorials](./tutorials/installation.md)
-2. [How-To Guides](./guide/usage.md)
+2. [How-To Guides](./guide/guide.md)
 3. [Reference](./reference/reference.md)
 4. [Explanation](./explanation.md)