I want to make a C# script for Unity to make the scroll view scroll up when I press "UP" key and scroll down when I press "DOWN" key.
Simply use
ScrollRect.horizontalNormalizedPosition // value range (0 to 1)
or
ScrollRect.verticalNormalizedPosition // value range (0 to 1)
try to lerp
these values accordingly on button click event handlers for up and down buttons.
Or you can have a look at scripts HorizontalScrollSnap.cs
and VerticalScrollSnap.cs
at UnityUI-Extentions