Build a child theme in 2017
Disclaimer: The method I am going to show you are the same that I have used personally and it worked for me. So take your time to do the correct way.
There are several way of creating a child theme. One of the easiest way is to use a plugin. There are several tutorial out there that shows how to use a plugin.
We are going to it manually, it only require some codes to function properly.
We are going to connect on your website server for that, using FTP access.
to proceed further we need 2 software;Filezilla[ FTP access]
Sublime [Text Editor]
A text editor will be quite helpful when copying code.