Help With Carousel Next Button

Hello,

I am using a really great template for a carousel slide (I think I may have found it here, actually), so I am admittedly not well versed yet in object interactions. I have two forward/back buttons which are being used to navigate through the carousel, but would like for my regular Next button to appear after the last slide has been viewed and the carousel next button has been hidden. I tried changing the state of my Next button to hidden and the start of the timeline and then using a similar trigger that was already in the template (when Textbox 1 stops interacting with Picture 9, change state of Next button to normal). The Next button was indeed hidden at the start, but instead of showing up after the last picture, it showed up after clicking the carousel button just once and sliding to the first picture.

Any suggestions are, as always, greatly appreciated. Attaching slide for reference.