There are so many ways to build a website. There are so many ways to build frontend.
So many procedures, workflows, pipelines, steps.
Build, Preprocessing, Post processing, Transpiling.
Linting, Unit Test, Integration Test, End to End Test
CSS, SCSS, Tailwind, Postcss, Bootstrap, Material Design
But you can most of the them in order to get started. No prototype, No Startup has to start with everything from get go.
These practices can be added, progressively once things settle in.
So just start working on the basics, improve it and once you settle than advance further.
Because basics like
(HTML + CSS + JS) are enough.