This guide applies to VR Flex units that have a Brother QL-700 Label Printer.
1. Locate the keys for your Flex, then unlock and open the enclosure drawer that houses the label printer.

You can find the lock on the backside of the VR Flex enclosure.
After unlocking the enclosure drawer, gently pull it open by placing
your hand underneath the front and sliding it towards you. The
drawer will open like a typical drawer, revealing the internal
components and printer.
2. Open the cover of the printer's roll compartment to access the inside of the printer.
3. Remove
the old label roll and label cartridge by gently pulling on the whole
piece directly upwards.
4. Unpack your new roll of labels, removing any tape holding the labels in place.
5. Place the roll of labels into the Roll Spool Guide slot.
6. Feed the loose end of the labels, label side down, into the feeder slot.
7. Close the roll compartment cover.

8. Close the enclosure drawer, then lock it.

Once
the label roll has been replaced, it is important to reset the label
count to ensure that any pending print jobs in the queue are cleared,
allowing the printer to resume printing.
Instructions to reset the label count can be found here.