Create Master Page using Design Manager in SharePoint 2013

Using Design Manager, you can create a brand new sites. 

We can convert an HTML file into master page file and customise your branding

Create an HTML file with your layout structure and apply CSS properly

Upload HTML and CSS file into sharepoint master page gallery under a folder "NewMasterPage"

Click on Design Manager -> Edit Master Page -> Click on Convert an HTML file into SharePoint masterpage. Follow the steps in wizard select HTML file from "NewMasterPage" folder

Your new master page is ready with few clicks. You can apply to this master page to your site!