Open the bag. If you have a Tumi with a combination lock, turn the tumblers to your three-digit code and pop the top open.
Pull up on the inserts to release the hook-and-loop fabric. Smooth the fabric down with your fingers if you wish a smooth-looking bag interior.
Reposition the inserts on the bag interior to accommodate your items or storage needs. Push the inserts down to engage the hook-and-loop fabric.
Pack items as needed in the newly sectioned portions of the bag interior. Move the inserts as needed.
Close the bag top, engage the lock if so equipped and head out on your travels.