@Jarolin, if you’re talking about a completely different “mobile-version” of your site, rather than a responsively designed site, you’d create the site just like your desktop version, using css and html, create a mobile sub-domain (ie m.example.com), store your mobile version in the new subdomain, then use a redirect to detect if the users browser is mobile.
Although there’s several different ways to redirect traffic, here’s a snippet provided on css-tricks https://css-tricks.com/snippets/javascript/redirect-mobile-devices/
