Step 2 and 3, for step 2, associative property should be commutative property, and step 3 should be associative property instead of the commutative property, i did all the work and its right, but how should i explain it?

I'm not sure if this is the answer your looking for but

the format should be something like :For step 2, you have to , so it should be the property instead of .
This leads to Step 3, where you/she (mistake), but this is wrong because your supposed to .
 
hope this answered your question :)