Noticed a few days ago comments about Pro Show Gol... (
I used to do my slideshow with ProShow Gold and upgraded to ProShow Producer about a couple years ago. I love ProShow Gold but love the Producer version better. Before settling on ProShow software (by Photodex) I tried a number of slideshow and video software but didn't like any of them. IMHO, ProShow tops them all.
For a starter with this software, I recommend trying ProShow Gold first. You can do slideshow (with video clips) embellished with transition effects and slide effects built-in to the software. If you want more effects and embellishments (e.g., wedding style, sports, etc.) you will have to download it, I believe $19.95 per pack.
I am not sure what your question is about soundtrack and copying captions to other slides. You can add music and other sounds to your slideshow. You can add captions to your slideshow. You can make slideshow mixed with video clips. You can adjust the volume of the background music or turn it off if you don't want it to interfere with the video clips' sound/conversation. You can adjust the time to start or end of your music according to your slide preference. You can also record only some portion of the music you choose depending on your preference. You can use background music from your collection or downloaded from iTune or Amazon, etc. (Caution: Copyright. For personal use, OK. If you post in YouTube, they will screen/scan and will deny if copyright issue.) You can also use built-in copyright free incorporated with the software. But, very limited selection. YouTube also has copyright-free music you can use but may not be to your liking.
In the slide style you choose, there is selection where you can add caption in the appropriate box. If there is no caption box, just click "add" in the caption layer and then type what you want. You can choose the style font, size, bold, etc. You can also place the text anywhere in the slide as long as it's not outside the border of the slide.
You can make copy of the slideshow you created on a thumb drive, DVD, Vimeo, and other post in social media of your choice if included in the software. ProShow Producer, you can make Blu-ray copy for great picture quality. Not sure if that's included in the ProShow Gold.
Of course, you can also call the company for help. I'm not sure if the trial version has the "Help" tab you can click if you have questions. The official version has them. Almost always, you can find the answer or instruction in the "Help" tab of the software and no need to call customer service.
IMHO, once you learn the "ins/outs" of ProShow Gold, you don't want to try anything else, except may to upgrade or buy the extra packs for effects and embellishments. Don't be discouraged. One more, have:
Patience, Perseverance, Practice!