Come on. Google is your friend. Also, this has been answered on FixYa before:
http://www.fixya.com/support/t8240303-looking_instruction_manual_stanley_fat
Don't touch the blade by hand use a pair of pliers. There should be a screw in the center of the handle, just remove it and you will see how to remove the blade.https://youtu.be/pFnbiw88Z8c