You need a good idea for a good app. If you already have an idea, find out if that kind of app already exists, who would use it and for what purpose.
You need professional help for this step. A person who has experience in creating applications will give you the best advice and explain you the complexity of making such app and what you need.
The design is a very important aspect when you create an app. The designer can show you several templates, and with your help, create the ultimate version of your app.
Programming is a crucial part of the application development where the initial idea is transformed into reality. In co-operation with developers, you can review each stage of the application development, share your thoughts with them and keep up to date.
The application is tested and checked for its quality. After the review, you need approval from the Google Play Store or the Apple Store, and after that, it is placed online.
According to users criticisms, inquiries and opinions, you supervise the application, maintain and upgrade it.