i read that the flash for the firefox browser is disabled, how do you activate it again? i know it might be prone from crashing but i want to test it for something aside youtube

i tried installing low quality flash 0.1 on micoB but nothing happens when i tap "restart". even when i close and open the browser again, it still says i need to restart the browser. fennec seems to install it with no prob. how am i going to know if the add-ons will work or not?