2) Agree in advance with the freelancer on all terms of cooperation, who is to do what and provide, because the freelancer wanted to shift his responsibility for part of the task, namely installing the code in the system and testing it, onto me as the contractor.
3) I was unable to verify whether the freelancer's code was working, as he refused to work in our closed system even after explaining why it is closed and how to access it. In general, be precise in confirming the terms of cooperation, and I believe the freelancer will be able to do his job.