Copywriting is a skill you develop through practice and repetition. You can't expect to just read something and become a copywriting master. This is especially true for people who are new to writing. The best way to learn copywriting is to just do it.
It's the same with learning how to drive a car, or learning how to code. The only way you're going to become a good driver, or a good coder, is to actually get behind the wheel and start driving, or open up your text editor and start coding.
And I mean actually write your first piece of copy. And your second piece of copy. And then your third and fourth, etc.
You can spend years in school or taking classes on how to become a better writer, but if you're not actually writing, it's all for nothing.
Start with writing short-form copy first, like an email message or a landing page headline. Then move on to something longer like a sales letter or long-form copy that includes multiple pieces of sales collateral like a brochure, catalogue, company profile or website copy.
Keep doing this until you feel confident in your abilities.
But what if you're not confident in your abilities? What if you don't feel like you're ready yet?
That's OK! You'll never feel ready until some time has passed, at which point it won't matter anymore because by then you'll have already begun your journey towards becoming a great copywriter.