So, I have seen these questions before and here is my take on this.
Linking from a list to a page should be done if the page is a dynamic page. What I mean by this? If you link to a page from a list, normally you would only need 1 screen with a set layout which would show data depending on which list item the user came from. This means that for example if you only have an image on the screen, then you would show the relevant image that belongs to the list.
Imagine it as you browse through a set of products in an online shop and if you click on a product, a screen comes up with the details of the product. If you notice, the layout of every product screen is the same, but the data and the text changes dynamically depending on which product is being viewed. This is because there is only 1 product info page and the data changes on the page depending on the product.
In your case you should have 1 layout on the page and change the data displayed on that 1 screen dynamically.
I have 3 list items and a product page. As you can see I only have 1 product page, but depending on which list item is clicked on, I would show different image and text that is pulled from the database and related to the specific product. This is how a linking from a list should function.
So here is your solution:
Create a collection called: Daily training (or whatever you want to name it). This will contain all days of all challenges. Create a filed called Video, another called text under the collection and whatever data you will need. You also need to create a relation to the posts. 1 post can have many days but 1 day belong to 1 post.
Once it is done, on the list: If button is clicked > link to the page.
Now if you navigate to the page, you will have the related day data available, so you can use magic text and image to say: Current day’s text, current day’s image etc.
I would also advise you to take a look at some video materials to get a better understanding of the basics.
Good luck with your app!
The working with data video explains it exactly what you need.