Do you need to start with the preparation of TOR or something else?

Question

Project management

The site and all its sections were located in one place (on the web, for example), each employee of the company had his own login and password, the actions performed in the system were recorded, and access rights to a particular section were differentiated.
Business scaling, opening additional stores, for stores there will be essentially the same interface, only with the data of their customers, in order to function separately from the main office, but at the same time completely depend on it and on the
main site.
Download price lists of these stores, some of their promotions ..
Provide our web service for third-party organizations (in the form of an estimate of auto parts numbers, displaying our offer via API, I can give examples)
Acceptance of goods using a scanner using a barcode or otherwise, issuing goods from a warehouse using a scanner and simultaneously posting it to accounting in 1s, automate the return of goods to the supplier.
Possibility of additional markups for customers or brands of auto parts.
Sending orders to the supplier by mail if the supplier is loaded using the price list. It happens that the supplier is loaded by the API service.
Calculation of salaries for managers who process orders (automatic calculation based on specified criteria). What kind of information on the site should be changed in the admin panel, as I understand it, that this is a CMS?
Automation with a client bank (receipt of funds from customers) expenditure of funds to suppliers.

Answer 1

You need to start with the formalization of business processes.
When you have an enlarged scheme in front of your eyes, it will be possible to separate processes and give them for automation or outsourcing.

Answer 2

Give it to a specialist. You didn't even manage to properly prepare the question.

Answer 3

The purpose of the TOR is to formalize the task in an understandable form for the performer. Therefore it is necessary:

• Understand the task and break it down into stages (coordination of technical details - system analysis, implementation and acceptance)
  
• Determine the resource who will do the project (people and their roles or one person and his role at different time stages of the project).
  
• Describe the task in terms that are understandable to each performer and do not allow for double interpretation.
  
• Based on this, make a brief summary and send it to the customer in the form of a TOR (this system analysis has already begun)