Underneath the drawers you will find a locking pin on each of the 2 drawer runners. This locking pin is shown in the image above near the front of the runner and holds the drawer in position.
Pull the locking pin on both drawer runners away from the centre of the drawer to unlock like above. To remove the drawer, it should now be lifted up and pulled towards you, see 3 images below.
Shown above is the up and down toggle which is used to adjust the height of the drawer.
Turn the toggle anti-clockwise to raise the height of the drawer and clockwise to lower the height of the drawer.
To put the drawers back in position just repeat the above process in reverse