Understanding the product that you are looking for will help you to narrow down your research to hire a Bigcommerce Developer. You can consult with the Application Development Company and get more understanding about your ideas.
Also, you should list down all the features and designs that you would like to have in your application. Once this is done, it will make it quite easy for you to select the right developer for your application and company. You can put your requirements online and get some profiles of developers, out of which you can finalize one.