How can I find users for this product?

You're selling forecasting software to businesses, therefore you need to reach out to businesses and sell it. They won't magically come to you. Once you have some credible customers use them as reference to get more.

For a product like this, a marketing campaign will not help you. Putting in maximum effort to find customers yourself to build credibility is what you should be focused on (vlogs/blogs are also a good way to increase credibility).

1. Find a business
2. Call/email the business
3. Pitch how this software will solve their issues.
4. Repeat 1000 times.

Also, for the love of god don't just send them that login form and say "Here, try it".

• Product walkthrough's
• POC's
• Live demo's
• Webinars

How the hell you prospects could understand what is this?

Start with a landing page and then somebody will understand “that’s for me”