Fatal error: Uncaught Error: Call to a member function bind_param() on boolean
If you write the code as I do in the video then this error is return by prepare($SELECT) inline 26 or by prepare($INSERT) inline 36.
The prepare() method returns false (gives an error) when you pass an incorrect query to prepare function.
In our case, we are passing $INSERT and $SELECT.
So make sure that the table name or column names (in SELECT or WHERE clause in $INSERT and $SELECT ) are correct (must match what you have declared in your database)?
Learn more about this error in StackOverflow: https://stackoverflow.com/a/27394772/7243731