Site not viewing properly

I’ve done something wrong and because of lack of experience I don’t know what I’ve done.
This morning I was trying to insert a meta tag in HTML code to have the site recognised by Google. I didn’t wake up to it being HTML and I was trying to insert it into CSS Home Template Page Template just above the line /*HOME Page Slider */
/*
* Template Name: Home Template
*/
get_header();

/* HOME Page Slider */
Now nothing works. As you can see above I’ve deleted the offending code however I must have accidentally deleted too much or something.
Can anyone help me please?
I do apologise but I was experimenting to see where I can place the meta tag and I still don’t know where to put it