Unresolved reference 'Import'

I am facing captioned error while I try to import any library. I am completely new to the coding, Python & Pycharm. Was trying to learn by looking at some videos which had first line of coding of Import PyPDF2 however I get error on this first line only. Can someone help me to fix this issue in simple language considering I am new to coding, Pycharm & Python. It would be helpful if somone gives help on each click & step,.