Ask HN: Being afraid and not knowing how to start building a startup concept

It involves a digital product, and luckily I am a developer. Before I go into any coding I want to have the concept nailed down and solid, and then commit to building it.

To start, i asked some advice in my office. I work with service designers, and they told me "refine your problem statement".

I'm currently panicking in front of a blank piece of paper at the moment. Fear of writing bullshit, fear of not knowing what to actually do, fear of it not being good enough, just paralysis. Total writer's block.

Unfortunately I procrastinate easily, due to fear of failing and due to me not being able to resolve questions such as "is this better than that?" in my mind. I would love for some kind of "process" or "structure" to guide me through the whole thing. How to get into a roll and keep building this thing, so to say.

I've read "the first 100" but i find that super vague and the thousand references the author gives keep distracting me. I think i need something a bit more rigid, like a set of tasks and examples for that on how to do it.

Is there any tool, process, formal way, that can help me through this? I don't mind paying for some product or course if it really adds some value. :)

Anything? :) Thanks <3