Sharepoint 2013 - Step to Create Page Layout using Design manager

To create a page layout
1.    Browse to your publishing site.
2.    In the upper-right corner of the page, choose the gear icon, and then choose Design Manager.
Gear icon menu,
 
3.    In Design Manager, in the left navigation pane, choose Edit Page Layouts.

  

4.    Choose Create a page layout

 

 5.    In the Create a Page Layout dialog box

 

 

6.    Click Ok,

SharePoint will creates an HTML file and an .aspx file with the same name.

In Design Manager, your HTML file now appears with a Status column that shows one of two possible statuses:

    1- Warnings and Errors
    2- Conversion successful

 
7.    Click the link in the Status column to preview the file and to view any errors or warnings about the master page.