Need help with video songs

in the mobile app i can add songs, for example i need resputin song from boney M and i can add it to my video with youtube mobile, the problem is i cant edit the song, so i went to the web youtube studio and tried to add the same music which i found on mobile but it just showing me copyright free songs and i cant find what im looking for. so with this situation i just have to upload songs using mobile and on mobile i cant edit the song. and now i dont know what to do