diff --git a/Testing-a-Pull-Request.md b/Testing-a-Pull-Request.md
index f7383d7..bb29c5c 100644
--- a/Testing-a-Pull-Request.md
+++ b/Testing-a-Pull-Request.md
@@ -12,6 +12,20 @@ Then, scroll down and download one of the artifacts:
 
 # Installing
 
-Firefox: https://blog.mozilla.org/addons/2015/12/23/loading-temporary-add-ons/
+### Chromium
 
-Chromium: https://github.com/ajayyy/SponsorBlock/wiki/Chromium-Unpacked-Install
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+https://github.com/ajayyy/SponsorBlock/wiki/Chromium-Unpacked-Install
+
+### Firefox
+
+Go to `about:debugging`
+
+Click "This Firefox"
+
+Click "Load Temporary Add-on"
+
+![image](https://user-images.githubusercontent.com/12688112/119751689-9ffe0380-be69-11eb-820a-0f4eed54c6d3.png)
+
+Extract the downloaded zip, and choose the `manifest.json` file inside it
+
+**Note:** The extension will be automatically deleted when you close Firefox
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