Fusion360 is what we use for electronic circuit design and board layout.This allows tight coupling to CAM manufacturing for enclosures and mechanical needs

Assembly of controller prototypes is a very meticulous process so the board can be brought up in stages. An accurate BOM or bill of materials verifies it is correct. It also proves the circuit design and functionality are as desired. It then goes to software development

Firmware development and testing. This is where the peripherals are exercised and driver code it tested. Then the UX or user experience is developed, which for Wi-Fi web pages are written to merge the HTML5, CSS and underlying hardware occurs.