Creating an inventory to link with current access database

I currently have an access customer database for my electronic repair company which holds all my customer details and jobs done for each. I would like to incorporate an inventory to the existing database so when a part is used on a job it is deducted from the inventory and I can keep track of stock levels. The database needs to be accessed simultaneously by two separate users on two separate computers on a local network. Example scenario: 1. Customer books in mobile phone for repair. Details are taken on computer 1 (shop front). 2. Engineer carries out repair and on computer 2 (workshop) completes notes and marks that a black iPhone 6 screen was used. - this deducts 1 iPhone 6 black screen from the inventory. 3. Job details and pricing is completed on computer 1 (shopfront) and invoice/receipt is given to customer. 4. Inventory will give alerts when items of stock fall below a given threshold. I have the access database working for customer, job details, invoicing etc, just need the inventory to be integrated with it. I would like to be able to add images to the inventory. I would also like a field added to the current database so I can add images to each job, for example before and after pictures of repairs.