Speak with Lucan again — if you’ve already done two rounds of Crossed Wands there will be no dialog options, and your character will automatically ask to use the training dummy. Otherwise, select the dialog option regarding the training dummy.
Cast Accio followed by four consecutive basic attacks
Make sure you have Accio and Levioso equipped in your Spell Diamond, then face the training dummy and cast Accio on it (hold and then press the face button Accio is assigned to). After sucessfully casting Accio, immediately do four Basic Casts by tapping .
Cast Levioso followed by four consecutive basic attacks
Next, target the dummy and cast Levioso. Directly afterwards quickly use four basic attacks to finish this combination.
Complete spell combinations without allowing the dummy to hit the ground
The third bit is trickier — you’ll need to cast Levioso, then do three Basic Casts, then cast Accio, followed by four Basic Casts. Levioso and Accio both hold the target in the air for quite a while, so don’t rush, and make sure you’re casting the correct number of Basic Casts.
Now that you’re done practicing with Lucan, you can continue on with Professor Hecat’s Assignment.