I am starting to design the architecture of my family's small hotel business. But I'm a junior js developper and I miss the big picture when programming on the go. I am afraid that this might lead to confusion and/or bad practices.
I have therefore started with a basic activity diagrams in order to document my ideas on the flow in the system. I want to be able to understand and forsee problems and catch them before i begin creating the implementation and to avoid spaghetti code (see below).
But I'm not sure it's the best way to start, and therefore need your advice. What kind of diagrams should I use to get the big picture and design the software before I start coding, in order to implement the business correctly into my program ?
I am still learning so please excuse my noobness.