How to check the implemented automated system?

Question

Project management

Good afternoon
We are implementing an automated project management system based on 1s.
The contractor sets up the system and writes "test".
It is not possible to test the system, because no one knows its capabilities, the performer writes disgusting instructions and quietly skips some of the system's capabilities.
Since we do not have a complete understanding of its capabilities, this point is missed.
Who acts in the implementation and verification?
What is required from the performer?
How do you end up testing the system?

Answer 1

It was you who should have told the contractor what features you need, and not first choose the system and then think about whether it is necessary.
1) You must have a test plan - test cases based on user scenarios (to do this, the user does .......)
2) You must write what you need and, based on this, the performer will write instructions.
3) Based on instructions.
In general, it sounds like "we don't know why we need it, but we did it, now we don't know what it does with what we did."
I can connect to the implementation phase and clean up if you need it. Contacts in profile.

Answer 2

The contractor must provide you with a special person "Introducer" (ERP Implementation Specialist), who accompanies the project from business process analysis to end-user training and project delivery.
Ask the implementer from the contractor, without implementers in any way :)

Answer 3

Require documentation, read your TOR which you yourself had to draw up