What is the problem here? You can definitely have elements on the top of each other, and hide them/show them with the hidable box on the left. You just need to make these elements not visible by default (check the box at the bottom of the property editor).
To show/hide elements when the user clicks on a button, you can either show/them manually with these relevant actions (Element section), or, better, define a custom state and show/hide elements based on the value of the state in the conditional tab for each element.
I have used a number (current page) as a custom state on the main page. It is just like a temporary store for something. I could have used text, but as you can see, having a number makes things easier.
Create a page, and add 3 Groups. Make them all hidden.
On page load I have set the state currentpage = 1 (so we always start at the beginning).
Create two buttons for forward and back. They add 1 and subrtract 1 from current page respectively.
Each group then has a condition that says "when current page = 1 (or 2 or 3) then become visible.
I then added a condition to the buttons so that if the current page is 1, then previous is unclickable.
And if the current page is 3, then Next is unclickable.
The nice thing about doing it this way is you can add many new groups, and all you need to do is set the condition on the group, and make sure the condition on the next stops at the highest number.