Write some Software for a website

Hi, We are looking to build a queue system. The product is as under - 1. We need to build a script that gets generated by the user. 2. The user drops the script in his website that will generate a dynamic widget. 3. When there are visitors to the users' website; they can enter name and contact details and this information is captured in a queue on the backend 4. On the front end, is a hybrid app (we have the code for the front end but the backend has to be integrated with the app) 5. The backend sends visitor information to the app that has requested for it Please let me know how we can build this.