I am new to JavaFX and so I apologize if the questions are obvious.
1. How can I set my checkbox choices to my genre instance from my movie class.
2. I am having issues getting my imageView to work and I am not sure why.
3. I am unable to get this line to write to my txt file
Why are you giving your Movie class all those setXXX methods? Why not set the fields from the constructor? If you have a no‑arguments constructor, you are risking having the object in an inconsistent state when you use it. In fact you are using the Movie instance to get its duration in line 78 before you set that duration. What goes wrong? Do you get a number format exception? Or does it record the length as 0?
I suggest you give the Movie class a toString method which produces the output to be used in lines 84‑85. Also give it a constructor taking a String of the same format. There is a little problem with that approach. It means you can never change the toString method nor that constructor once they have been finally implemented.
Can you get the duration from the slider as an int from some property or other?