Product page is where you sell the value of your product and where the user takes action (adds to cart, sign up, makes a purchase, etc.).

1. Name of the product.
2. Value proposition: what's the end-benefit of this product and who is it for?
3. Specific and clear overview of what the product does and why is that good (features and benefits).
4. What's the pain that it solves? Description of the problem.
5. List of everything in the product (e.g. curriculum of the course, list of every item in the package, etc.).
6. Technical information: parameters, what do you get and how does it work?
7. Objection handling. Make a list of all possible FUDs (fears, uncertainties, doubts) and address them.
8. Bonuses (what you get on top of the offer).
9. Money-back guarantee (+ return policy).
10. Price.
11. Call to action.
12. Expectation setting: what happens after you buy?

What you now have in place is like a skeleton. Next step would be to start writing the draft version of the copy by filling in the blanks.