How to put one element under another?

Question

css

I need to place the element from the first screen under the element from the second screen.
I tried different z-index values, it only helped z-index:0;for the bottom element, but z-index:0;the slider functionality does not work with it.

Answer 1

Give the first element Give the z-index: 1;
second elementz-index: 999;

Answer 2

Wrapper position: relative
to what needs to be pushed under position: absolute z-index:-1

Answer 3

and flex-direction: column have you tried?