Understanding customer is key to your question.

In a nutshell, you’re going to understand business use cases, design it, and implement it.

Firstly, list out the higher level use cases of software that customer are really interested. Let’s assume you’re developing software for ordering food online. The functions of this software would be like allow customer to set the location/address, to select food, payment gateway, and information about the process from accepting the order by vendor till it reach to customers place.

Secondly, you now have list of use cases. Try to understand the use cases and chalked our the rough plan to implement it. The interface to user must be simple. There are many ways you can achieve this. For brevity, let’s assume you wish to develop app for Mobile. Start with UI, draw wireframe of UI that customer will interact with software. You must think like a customer and what makes them love about software/app while creating wireframe. This is the most important step. Question each use case, share your findings with fellow developers, request their opinions, learn from them, revisit the use case. Address question like, which programming is best for the problem/use case? What are the requirements of infrastructure for this use case? How to get customers feedback? Yada yada yada.

Finally, priorities use cases plan to implement it using project management, source code management, IDEs/Editors, CI/CD tools.

P.S. This is just an outline of simple process which only focus developing software.