The owner's manual doesn't give instructions on how to disassemble the mags for cleaning. I assume they aren't intended to be taken apart by the average user. It looks like you would have to damage the magazine to get it apart. If there is a way, I'd like to know it too.
There are two rectangular impressions just above the base plate. The base plate slides off parallel to those indentations i.e. perpendicular to the back of the magazine and not parallel to the bottom of the magazine.
Older magazines have a button that goes through the baseplate that you can depress with a small screwdriver or punch in order to release the baseplate. Newer magazines have a thingamabob that hold the baseplate in position internally. To release it you need something like a dental pick that will go into the long slot in the magazine and pull the spring away from the baseplate. Once it has been pulled up the baseplate will slide off.
There are two rectangular impressions just above the base plate. The base plate slides off parallel to those indentations i.e. perpendicular to the back of the magazine and not parallel to the bottom of the magazine.
I resurrected an old topic but I asked for help and wanted to comment that it worked for me. I did have to figure out the mag spring had to be pushed up out of the way first.