I am a big fan of yours from today! I have followed your instructions to set up a child theme successfully but when I started to move sections of code. (I want to put the header above the menu) I got this message;
Unable to communicate back with site to check for fatal errors, so the PHP change was reverted. You will need to upload your PHP file change by some other means, such as by using SFTP.
could you give any advice?
How did you move those sections? Did you do it inside the back end of wordpress? If you did and now the website is not loading you can access the files of the wordpress installation by using FTP client (like filezilla) or by going on your cPanel and then file manager. Find the file you changed and change it back.
the first thing you should try is undo the changes you did. You should always keep a backup of the files that you edit when changing the code. If you dont have the file then you must take it from the theme that you changed. After uploading the original file everything should work fine. If you want more help you should give more information cause now I am just guessing