My skills:
power electronics design
PCB layout
embedded systems
based on my experience, I can tell you that a project like you describe needs at least 10 day of work to finish it.
I have worked developing similar embedded systems, the process begins with the planing acording to requerings (what we want?), a list of exact features of your product, so acording to the plan, assigning activities, timing the activities, monitoring the activities while they are beeng developed (in case more than one person develops the project), in this case you only need the diagrams and code so there is not lab and field test
conclution. I could give you the information but there is no way to ensure the PCB protopype is going to work correctly without test
greetings!!