diff --git a/README.md b/README.md
index c269dae..868fc17 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,21 @@ Thunderbird 115+
## Installation
- Install
+ 1. Enable userChrome in Thunderbird:
+ > Navigate to Settings > General > Config Editor
+ > Search for **toolkit.legacyUserProfileCustomizations.stylesheets**
+ > Toggle to 'true'
+
+ 2. Locate your profile directory:
+
+ > Navigate to Help > Troubleshooting Information.
+ > Under the Application Basics section, find the Profile Directory row, then click on Open Directory. Your profile folder will open.
+
+ 3. In your profile directory, create a new folder called 'chrome'.
+
+ 4. Add **userChrome.css** and **userContent.css** to the directory 'chrome'.
+
+ 5. Restart Thunderbird.
## Licences
Nu-grey-theme for Thunderbird is available under a [GPL3 license](https://github.com/cybrkyd/thunderbird-theme/blob/main/LICENSE).