I am totally new to raspbian Lite and not know how to install opencv on this os. I need this for my school project which is written in python. I am trying this https://gist.github.com/willprice/c216fcbeba8d14ad1138 but when I run this script, this is giving many errors that I am unable to understand.
Being two years old, that script has issues such as tying to an older version of OpenCV. Rather than downloading from Itseez's GitHub repo you're better off installing via the Raspbian package repositories.
sudo apt update sudo apt install python-opencv