Active voice or Passive voice? Need clarification

Hi,

Should I write in the active or passive voice in my essays? I have heard that it is better to write in the active voice however in my recent essay I have written mainly in the passive voice and am unsure of how to change my sentences into the active. For example, 'Shadow puppet theatre is based on Javanese versions of the Hindu epics Ramayana and Mahabharata.' 'Major scenes are accompanied by longer structural units.' 'Lighter pieces are used to entertain the audience.'

Can you help me?
The essay question is: Write about the use of gamelan music to accompany shadow puppet theatre in Java.

u should write in the active voice.
actually all the sentences u wrote are in the present

I have been doing some research I think I kind of get the idea:
instead of 'Major scenes are accompanied by longer structural units.' it would be 'Long structural untils accompany major scenes.' and instead of ''Lighter pieces are used to entertain the audience.'

it would be 'The audience is entertained by lighter pieces' or 'Lighter pieces entertain the audience.'
Is this right?
Is it a better way to structure my sentences?

You got it. Can you feel how much more powerful it is? Instead of, Kevin was killed by a man with a hammer, you write, "A man killed Kevin with a hammer!"

It is so much more assertive...