I have not looked in your sample but you want to create panel within your canvas. I name mine ScrollView and attached is the Scroll Rect and mask. set the scroll rect to verticle, elasticity to .1 and sensitivity to around 25.
It is important that the Content of scrollview is filled with the container panel that will be a child of the View panel. Also is important if you want a scrollbar that you place it as a child of the view panel then click the view panel and drag the bar to vertical scrollbar within the scroll rect
If you don't have a container panel as a child to the ScrollView create one and within the Container panel Add a grid layout group and set the start corner to upperleft the start axis to verticle the child alignment to uppercenter and constraint to fixed column count, set constraint count to 1.
Next add to the container panel a content size fitter and set verticle fit to min size and horizontal to uncontrained also the rect transform of the container panel set Pivot Y to 1 so it starts at the top of the list.
After this is all set up anything that is a child of the container panel(Multiple created text objects, input fields, images or even Instantiated panels) should scroll just fine and be fitted perfectly in the container.