Video is nothing without a good video. It will call a silence of disability video when you provide a wrong audio or sound selection. In order to find your audio needs, you will need a service that provide a colelction of audio for your video creation project. Then there are Audio Blocks website that will give you a solution for your audio needs. If you want to try it then you can refer to audio block group buy, this is because the real audio block website will cost you a lot when register.
I will recommend you to buy an account directly from audio block if you are satifsied with the service and willing to receive more updates and support the developers. As I know, nowadays Youtube has a strict rules on monetization, a channel will be need to have a 1000+ subscriber and 4000 hours of watching time before the channel can be monetize. This is a challenge for video creator like you to create a great video that will engange visitor to subcribe and watch more to your videos.
Turning a slideshow video is also can be choice of people on creating video and it will be great if you can add good audio to them. Not only a music but I will recommend you must add a sound effect to give more engangement to the visitor and make the video become favorited by user and user will give a like for you even without you asking them for it.