added CSS instructions

README.md

@@ -13,6 +13,7 @@ This includes our [Divi Form Builder](https://diviengine.com/product/divi-form-b
 3. Click on the `Portability` icon (2 arrows).
 4. Click on the `Import` tab.
 5. Import one of the layouts by uploading the `.JSON` files.
+6. Copy all the CSS from `style.css` and paste it in `Divi` > `Theme Options` > `Custom CSS`.
 
 
 ### More informations