Show Records to admin Using Customize Table in Wordpress

I am new to Wordpress and I want to show the record from custom Table in

Admin Panel. I did R&D and Found wp_list_table but I did not get how to Create a file and where it will be located.

I got this link where step by step mention

http://ift.tt/H6mCBK

But I don't know where I have to create and locate as well as call this file.

One file is already I found in wp-admin\includes\class-WP_List_Table

I am confused that this located file will be used or I have to created a new file

via Chebli Mohamed