I added the three tacks I wanted to mix into Cubase; I decided to add three tracks, of the same melody of the song.

I then match the audios together and fit the violin instrumental with the piano

After equalizing the violin and the piano, I decided that the violin was too quit, but it has another sound within it that distracts the piano, so I decided to use the equalizer to drown out the unnecessary sound and high the violin.

I cut up the drum instrumentals and selected the part of the track that matches the song, and duplicated that part into the entire song

I then decided to do the same thing with violin instrumental