A:Answer Pop the razor head cover off the razor.
Thereplacement blade box has a tool(orange in my box) that fits over the flange on each razor head, attach,squeeze and rotate about 1/4 turn counterclockwise and lift out each blade.
Clean the razor cover, then replace each blade in the reverse of above directions.
Pay attention, the blade head only fits a certain way and will not seat or lock in unless correctly inserted.
Hope this helps