How do I pu t music in my slideshows on movie maker and put them on youtube?

I cant figure out how to put music in my slideshows. and when i try to put it on youtube, it says i doesnt work! HELP!!!!!
Download, convert and save videos directly from Youtube and more.
Formats:

-AVI, MPEG, WMV, MOV,
-MP4 (Download faster in High Quality and HD) *Recommend
-3GP (Download faster for Phone)
-FLV (Download faster - Rename file .FLV - Example: Namevideo.flv)
-MP3, WAV (Audio Only)

1. copy the video url (Example: www.youtu . . . .)
2. go to Forinside
3. paste the video url in the url box
4. select format (AVI, MPEG, MP4, 3GP, WMV, MP3, FLV, MOV, WAV)
5. Click download

* Moreover, it can convert local videos on your PC in the formats above.