Clawing is a different method of catching a ball & is also known as snatching. It is a very useful 'recovery catch' & is also used in many other moves. Normally you catch a ball by waiting until it drops down into your hand with your palm facing upwards. To make a claw catch, you swing your hand over the top & catch the ball from above with your palm facing down.
As always start with one ball. Throw it to one hand, wait until it is at just above waist height, then still using inside scoop, swing your hand up on the inside of the ball then bring your hand down on it from above. Be careful if you are learning this trick using tennis or other bouncy balls as you will probably bat a fair few into the floor with great force causing them to bounce everywhere.
The throw is also made with the palm facing down. Flick the wrist back (not too hard) as you release the ball to move your hand out of the way so that it doesn't stop the ball from rising & to prevent it from flying forwards. Keep clawing the ball back & forth until you can make every catch without leaning or stepping forward.
Now put it into a Cascade. You know what to do: one at a time, same ball each time, every right, every left & finally every ball. When clawing every ball you may find yourself holding your wrists back so your fingers point backwards & letting the balls fall into your hands. It may be easier (juggling isn't supposed to be easy) & although it is technically a claw catch it doesn't look as good. Lean over the pattern & swing down on the balls as they reach waist level.