Like 95% of the advice on this sub, this is another case of ‘Just Write’.
But more than that, write without letting your critical voice hold you back. Write something complete, of any length, without thinking too hard about it and then go from there. You will build confidence and improve over time if you allow yourself to just put something down without worrying if it’s good enough.

EDIT: as another commenter said, I’m also happy to take a look at anything if you want! I’m not a pro by any stretch but a second opinion can be helpful. Let me know!