Save the file bellow as anything_you_want.pem
The easiest way to save it is to click the raw button to see only the text, and then use your browser's file>save menu.
On Firefox, open the Options screen. Click the Advanced tab. Then click the Certificates tab and then the view certificates button.
Click Import and search the file you just saved. If you forgot were, just save it again :)
Select the option: Trust this CA to identify websites (it is usually the first, but may change, so check the text) and click OK.
End of part 1.
Now close all the certificate windows and go back to Firefox's Advanced options. Now click the Network tab. And then the Settings... button next to "Connection"
Now set proxy to Manual and enter:
Http Proxy: 10.75.202.24 Port: 8888
and check: [X] Use this proxy for all protocols
Click ok and you are done.
common sense says to never trust a proxy like this. Test logged off if possible. And disable the proxy as soon as you are done.
To disable the proxy, on Firefox:
Options > Avanced > Settings... (next to Connection) > [x] No Proxy > OK and you are done.
Better yet if you also delete the Bogus Certificate. Open the Certificates window, and delete everything with "Charles Proxy" in the name. (should only be one if you followed these instructions).