Select the devices you wish to target with your media queries. Then copy/paste the media queries into your css file.
This CSS Media Query Generator operators on the principle of Progressive Advancement. Progressive Advancement means that when we design a website, we first create a version for smaller devices with less real-estate (like a mobile phone). This version includes the most basic functions & features. After that, we create more advanced versions for a tablet, laptop, and desktop. These are created by adding more more complicated effects and interactions for larger screens and different devices.