1 Write down all known app requirements, every detail
2 From that document derive two more documents (a) a detailed list of the data requirements from step 1, (b) a document that relates those data requirements to UI requirements.
3 From 2(a) build a database design using a method like https://www.artfulsoftware.com/dbdesignbasics.html, build and test the database as described in that link
4 From 2(b) and the result of 3, write a detailed GUI spec, and write its pseudocode
5 From what step 4 produces, decide what frontend software you wish to use
6 Write debug and test the app
If you're not a developer, you may need a developer's help starting at step 2, definitely by step 3.
Last updated 16 Aug 2019