branding access manager nidp.jar

Hello! I want to change the text that is highlighted on the screen.

I am trying to follow instuction steps:
But I don't have these actions:
  1. Unzip the copied nidp.jar file by using the following command:

    jar -xvf nidp.jar

    How do you perform this action?
    Or maybe there is another way to unzip the nidp.jar file?