Update Existing Stock Manager Advance Script

Please read all the instructions carefully before bidding. I have bought Stock Manager Advance with point of sale Script from codecanyon. Check all features and demo here. ([login to view URL]) At this time it is a script for only one shop i.e. one owner can only one shop under the script. We can create warehouses and new users also but only for the same business. for example there are three users 1,2,3 having three shops X.Y.Z. Using this script one user 1 can only handle shop X. If user 2 wants to handle his shop Y or user 3 his shop Z then they will need to install script again and after that they will be able to do that. What i need. I want to add functionality that new user can directly register them selves and can manage their shops. I.e. user 1 will register and after login he will be able to see only shop X's details can manage the same, user 2 will register and after login he will be able to see only shop Y's details can manage the same he will not be able to see user 1's details. same for the user 3. This is ongoing project. This task is just for testing of freelancer's eligibility. If i will satisfy with your work will be hire you again and then pay vary good amount. Other queries and doubts will be cleared on private chat. All the best. Happy bidding