how to install blades

Just push the full cartridge of blades into the bottom of the handle, Boom your loaded.

You have to be a little more specific. There are numerous knives ranging from the simple pop open to the taking it completely apart. Generally there is a screw that you remove that separates the knife in two and you would install the blade in the top where the blade grooves are lined up. Make sure to use the same type blade as you are replacing being they are not all universal.