I need to decide what should be proper relational database schema for the following scenario:

There is a computer sales and maintenance store. The store’s services include computer sales, repair computer parts and installing and
upgrading software and hardware.

The store has a number of branches.
There are a number of personnel working in each branch.
Personnel can be reassigned to other branches to work.

The database should include at least information about the following:
• Details on sales and services provided
• Details on employees
• Inventory details
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I made the following tables:
Branch {branch_id, manager_id, name, address, phone_no, email)
Employee {employee_id, name, age, date_of_joining, address, phone_no, email, salary, expertise}
Service {service_id, description}
Item {item_id, name, description, brand, model, cost}
Branch_Service {branch_id, service_id}
Branch_Employee {branch_id, employee_id}
Branch_Item {branch_id, item_id, quantity}

The first field listed of each table is primary key.
Relationships between tables
1. branch_id of Branch_Service is foreign key of branch_id of Branch.
2. service_id of Branch_Service is foreign key of service_id of Service.
3. branch_id of Branch_Employee is foreign key of branch_id of Branch.
4. employee_id of Branch_Employee is foreign key of employee_id of Employee.
5. branch_id of Branch_Item is foreign key of branch_id of Branch.
6. item_id of Branch_Item is foreign key of branch_id of Item.
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Could you please check and suggest any improvement in it? I am not sure if tables will provide information about Inventory details properly.