Helvetica Neue is not working on windows browsers

After Research, I conclude that the Helvetica Neue is not web safe font. so we need to buy the license or to apply the following https://css-tricks.com/snippets/css/better-helvetica/.

body {
   font-family: "HelveticaNeue-Light", "Helvetica Neue Light", "Helvetica Neue", Helvetica, Arial, "Lucida Grande", sans-serif; 
   font-weight: 300;
}

It's the last applicable only for the light mode? what if I need to use the bold one?

this is my font face:

@font-face {
  font-family: 'Helvetica Neue';
  font-weight: normal;
  src: url('../assets/fonts/Helvetica/HelveticaNeue.eot');
  src: url('../assets/fonts/Helvetica/HelveticaNeue.ttf') format('truetype'),
    url('../assets/fonts/Helvetica/HelveticaNeue.woff2') format('woff2'), url('../assets/fonts/Helvetica/HelveticaNeue.woff') format('woff');
}

@font-face {
  font-family: 'Helvetica Neue';
  font-weight: 500;
  src: url('../assets/fonts/Helvetica/HelveticaNeue-Bold.eot');
  src: url('../assets/fonts/Helvetica/HelveticaNeue-Bold.ttf') format('truetype'),
    url('../assets/fonts/Helvetica/HelveticaNeue-Bold.woff2') format('woff2'),
    url('../assets/fonts/Helvetica/HelveticaNeue-Bold.woff') format('woff');
}

any useful link explain how to use the license after purchasing