There is a stretch between launching and earning that no amount of building shortens. You have a product, it works, and nobody knows it exists. Most advice at this point is marketing advice, which is written for businesses that already have customers and is close to useless when you have none.
The first ones are different. They do not come from campaigns. They come from finding the specific people who already have the problem and talking to them directly, which is uncomfortable and works. What gets you the first ten will not get you the next fifty, and knowing when to change method matters as much as the method itself.
This cluster covers that stretch and nothing else:
Where your customers already gather, which is usually somewhere unglamorous and specific. Founder-led sales when you have never sold anything, which is mostly listening and asking. Outreach that gets replies, and the reasons most of it does not. Communities, directories and launch platforms, and which are worth the effort. Partnerships and content, once you have enough customers to know what to say. The point where manual stops working and something repeatable has to replace it.
We are not covering growth. Growth is what happens after you have proof that someone will pay, and confusing the two is why people run ads before they have a single customer.