Can someone help me in javaFX (Beginner)

Question

***what i need to do :
*a window that contain a "choose a location" button
*in the center an image previewer and a video player at the same time
*a next and previous button so i can switch files in the same directory after i have chosen it

***my problem:
-i already did the location button but i don't know how to link it with my mediaplayer
-how can i display videos and images for one location (how im going to filter to preview the images OR play the video)
-how im supposed to do the next button

Answer 1

for the next button
i thought of an event when you press the button the index incremets by 1
i don't know if its right tell me your thoughts
and sorry for my bad English im french educated

Answer 2

im following tutorials but im stuck on something

when i create fxml file and add an imageview using scenebuilder (with id: imv)

making image view in main with the same id (imv) and adding an image using imv.setImage(image) does not