How to hide a button and then reveal

Hi! I am using the new Adobe Captivate. I am new to Adobe Captivate, so I am still learning. I have a slide that includes a dropdown menu. I would like to hide the button upon entry on a slide until the user visits each drop-down item, and then it appears for them to move on to the next slide. Can someone help me with this? If you can add screenshots, that would be extremely helpful. If not, I am a quick study, and I believe I will be able to learn without the screenshots.