This is a very fun assignment to do in which you will need access to Audacity. First you will need to find a song that you would like to slow down. I like to look through free sound websites like http://www.bensound.com/royalty-free-music/2. If you feel risky you can find downloads of songs that are not royalty free, but this could cause some trouble, so I like to stick to the royalty free music. Once you find a song you really like you can download it to an mp3, so it is easier to upload to Audacity. After you download it open Audacity and drag the file into Audacity so it can upload.
When the song has uploaded you can then go to the effects tab at the top of the page and scroll down to change tempo.
A box will pop up and you drag the button on the sliding tool down to the end to drag out the tempo. Then hit ok and it will change the tempo to drag it out slowly.
Then you can export the sound and upload it to Soundcloud for everyone to enjoy.