How to organize and create a project?

Question

Preparation of terms of reference

Good day everyone!
I need your help / advice, I am ready to consult for a fee. There is an Internet site for the sale of goods, the site was written a long time ago and does not suit a lot of things (now we are facing problems with failures, etc.), the programmer worked remotely. The current site was created in php + mysql, and also written in a straightforward code, orders / customers / suppliers can only be processed in separate programs from the local computer. Does it feel like something is wrong here too?
Therefore, we want to create a new one, but we don’t know what tools to use and what to write on, a lot of things have been studied, but there is no understanding of what is best and most correct to choose.
It is necessary to create a website with the ability to interact with 1s, to establish the acceptance / issue of goods using a scanner.
Open branches on the same site and provide the ability to process orders, customers and other opportunities for this branch.
Create additional catalogs for the selection of goods with the possibility of their further filling.
Properly organize product pages so that the pages are indexed in search engines.

Answer 1

Write a technical task, where to list all the Wishlist.
You can draw an approximate UI at least with a pencil.
Structuring TK.
Try not to mention specific technologies if you are not sure what exactly you need.
You can do part of this work and hire a person who will help identify incomprehensible places in the TK and bring it to the ideal.
Hire a programmer/office to do it.
The migration of data and current processes from the old system to the new one can be described as part of the TOR and specify the criteria (without stopping the service, or the possibility of temporary work in two versions at once, or with downtime of no more than xx days), or find out convenient options with the contractor.