All of these steps are part of the development planning process. There are times when people fail with the things that they are developing because they did not follow the proper process. You need to be familiar with the process that you should go through because it will make things easier to understand.
It is best to start with an analysis of the current market. You can also assess if the current market will be able to take the idea that you have in mind. There are some ideas that are good but you cannot use them yet because the timing is not right. The development process will help you determine this.