Add setup and usage instructions

Co-authored-by: Daniel Otero <[email protected]>

Author: inaki-amatria

README.md

@@ -1,6 +1,47 @@
-tree-sitter-fortran
-==================
+# tree-sitter-fortran
 
 ![Build Status](https://github.com/stadelmanma/tree-sitter-fortran/actions/workflows/ci.yml/badge.svg?branch=master)
 
 Fortran grammar for [tree-sitter](https://github.com/tree-sitter/tree-sitter). Adapted from [this Fortran grammar](http://slebok.github.io/zoo/index.html#fortran_f90_waite-cordy).
+
+## Setup and usage
+
+> [!IMPORTANT]  
+> Prefer using the `tree-sitter-cli` installed from `npm` as shown below. This
+> is to ensure all developers use the same version of `tree-sitter`, avoiding
+> compatibility problems.
+
+Follow these steps to set up and run `tree-sitter-fortran`:
+
+1. **Clone the repository**
+
+2. **Install dependencies**
+
+    ```sh
+    npm install
+    ```
+
+3. **Generate the parser**
+
+    ```sh
+    npm run generate
+    ```
+
+4. **Run the tests**
+
+    ```sh
+    npm run test
+    ```
+
+5. **Update the tests (if needed)**
+
+    If you have modified the grammar and need to update test expectations:
+
+    ```sh
+    npm run test -- --update
+    ```
+
+6. **Check `highlights.scm` (if needed)**
+
+    If you have changed nodes used in `highlights.scm`, review and update it
+    accordingly. Even if tests pass, outdated highlights may need fixing!