Sometimes getting a quick visual helps a lot. Please see below for videos demonstrating how to attach blades on Preserve razors.
Attaching your Blades
PRESERVE SHAVE 5 or POPi SHAVE 5
PRESERVE SHAVE 3 or PRESERVE TRIPLE RAZOR
Trouble Shooting the connection:
If the arms arms are not nested under the clips on the back of the cartridge, the cartridge will not stay properly attached.
Use fingers to move the arms out.