How do I use Firefox extensions?

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Tags

1. #extension
2. #countdown
3. #about
4. #brief
5. #after
6. #select
7. #appear
8. #install
9. #installation
10. #takes
11. #active
12. #firefox
13. #seconds
14. #theme
15. #window
16. #downloaded
17. #would
18. #button
19. #click
20. #first
21. #software