diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 594ff89..1272200 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -1,7 +1,18 @@
-## CONTRIBUTING
+## Contributing
 
 - Fork it ( https://github.com/stisla/stisla/fork )
 - Create your feature branch (`git checkout -b my-new-feature`)
 - Commit your changes (`git commit -am 'Add some feature'`)
 - Push to the branch (`git push origin my-new-feature`)
 - Create a new Pull Request
+
+## Note
+
+### CSS
+If you want to make some changes in the CSS style. Don't edit the `.css` file, use the SCSS file instead.
+
+### HTML
+Since we use Nunjucks, if you want to make changes to the HTML structure, make sure you change the source file (Nunjucks) located in `sources/pages`.
+
+### Important!
+It's better to use the code guide by @mdo. Before making a pull request, make sure you have compiled all source code such as SCSS, HTML and others. Most importantly, make sure your changes have been tested cross-browser and still use existing variables (if possible).