Due to the fact our new weapons have detailed grips and are much smaller than previous weapons, we decided to put up a couple of tips for inserting and removing TS weapons.
TM-9 insert as you would a regular minifig weapon, from the front of the hand. To remove, pull it out of the minifig's hand vertically.
TG-17 inserts side ways into the minifig's hand and then rotate 90 degrees. To remove you can do the same as inserting or pull it out vertically.
TTK inserts vertically into the minifig's hand, there are two small bumps on the side of the handle that will help securely hold it in place. To remove just reverse the process by pulling the knife out with a vertical motion.