How to switch to font-display?

Question

Google Fonts

I have right now

@import url('https://fonts.googleapis.com/css?family=Roboto:500,400italic,700italic,300,700,500italic,300italic,400&subset=latin,cyrillic');

I want to make a new one

@font-face {
  font-family: 'Roboto';
  font-display: auto;
  src: local('Roboto'), url(https://fonts.gstatic.com/s/roboto/v18/KFOlCnqEu92Fr1MmWUlfABc4EsA.woff2) format('woff2');
}

Only now I did not understand how to use the necessary styles for me?
500,400italic,700italic,300,700,500italic,300italic,400&subset=latin,cyrillic