They got simplest tutorial here: https://www.w3schools.com/js/default.asp .
That’s how i started.
How far have you gotten on the FCC curriculum? When you get stuck, post a question on the forum and show us your attempt at a solution and ask detail questions about what you do not understand. We will do our best to point you in the right direction so that you can hopefully figure it out mostly by yourself.
Like learning a foreign language, it takes lots of practice until it becomes easier to implement.
If you need more hand holding, check out online video courses like Lynda.com or Treehouse. Many public libraries offer subscriptions free of charge, and they will walk you through some simple projects. In the end, you’ll just have to do it. There are no shortcuts. The chances are you know more than you think you do.