Excuse my ignorance and stupidity, but I'm trying to set up Post Grid. I know how to insert the short code in my sidebar but can't for the life of me work out exactly where to paste your PHP code. There are several PHP files in my WP Twenty Seventeen theme. Please help this dimwit if you can...
Welcome to our forum.
if you are not sure about use of php code please ignor it,
instead of php code you can use basic shortcode
[post_grid id="1234" ]
if you want to to use on sidebar just use via text widget will work fine.
Let me know if you have any issue.