Correct. When the baseplate is slid into position the arms will tend to tilt towards the front of the front of the magazine. Pull the arms rearward and they'll snap in and retract into the baseplate.

Once you've done it a few times you'll get the knack of sliding the baseplate and the holding the arms in just the right manner for them to pop into place together.

A Qwik-Clamp makes a good "third hand" for the procedure if one lacks vise.

An incredibly stupid design that complicates the normally simple task of cleaning and maintaining one's magazines. Many users may want to simply adopt a cleaning procedure using a polymer-safe aerosol pressure blast product.