Read the character, not its sound
Cangjie uses character shapes and letter keys. You do not need to supply a Mandarin or Cantonese pronunciation. A root label is a memory aid for a key; it is not a pronunciation to type.
The first ten exercises introduce single-key characters. The next eight combine familiar shapes. The final six mix repetition with longer codes, ending with a five-letter example.
These exercises check selected full codes supported by this site. Other Cangjie implementations can have differences. A code accepted by a permissive lookup is not always the complete code being practiced.