Step 1: Go to the Firefox download webpage
Visit the Firefox download page in your pre-installed browser, such as Safari.
Step 3: Move Firefox to the Applications folder
Once the download has finished, the file should open by itself and pop open a Finder window containing the Firefox application. Drag the Firefox icon on top of the Applications folder in order to copy it there. This action will begin the installation, which should only take a few seconds to complete.
Step 4: Eject the Firefox installation file
After dragging the Firefox app to the Applications folder, go back to the desktop screen, move the mouse cursor over the Firefox icon, and click it while holding down the
control key on your keyboard. Then select the
Eject Firefox option.
Step 5: Open Firefox
You can now start Firefox by double-clicking on it in the Applications folder. The first time you open Firefox, you should receive a dialogue box that asks you if you are sure you would like to open Firefox. Here you should click