You will have to update to OS X 10.9 to be able to install Firefox 49+ versions.

See:

• https://www.mozilla.org/en-US/firefox/49.0/releasenotes/

[FX:49]:Ended Firefox for Mac support for OS X 10.6, 10.7, and 10.8.
[FX:49]:Ended Firefox for Windows support for SSE processors

I know I need up update to OS X 10.9. I need to know how or where I can get this done or even if I can get it done.

https://support.mozilla.org/en-US/kb/firefox-osx

As to whether your hardware is compatible a list of Macs that is compatible with "Mavericks" is at http://www.everymac.com/mac-answers/os-x-10.9-mavericks-faq/os-x-mavericks-compatible-macs-system-requirements.html

https://support.apple.com/kb/SP702

Requirements for OSX 10.12 "Sierra". https://support.apple.com/en-us/ht201475 https://support.apple.com/kb/SP742 http://osxdaily.com/2016/06/14/macos-sierra-compatibility-list/

My Mini is a 1.1 and I believe is from 2007. It is not compatible with Mavericks or Sierra. I have Snow leopard on it now. I need to know what has to be done to the computer itself to allow me to keep it and update the operating system. Thank you.