You are going to face demands, objections and hassles...

To anticipate and be able to deal with them methodically, put together a presentation document, also called "opportunity study" or "business case".

The following questions will help:

Solution
What are the specific objectives of your project? What does your solution actually consist of?

Team and stakeholders
Who will be in charge of the project? Why are they the right people? How does everyone find their way around?  Will the team need other contributions?

Cost
Which investments are strictly necessary? Who finances what? Over what period of time? To cover which priorities?

Impact
On a societal, human, operational, economic, commercial level... what gains, what benefits do you estimate for the organization?
What income for each one?