Would it also be right if I put saya before harus?
In such a structure, nothing comes between 'saya' '(the agent) 'lakukan' (the verb).
This is a passive type two sentence.
It's the same structure like this sentence :
Thank you - your explanations are always very clear
Switched the order of aku and harus. I believe both orders are spoken and understood (acceptable.
You can say it like that and you will be understood, but it's grammatically incorrect.