how to get 2 channels on the 5.1 stems (homemade)

hello recentily i know how to make 5.1 audio form a stander mp4 file or mp3 

but it allways does this am i doing something worng here and what is the fix plz that would be such a big help out

as you can see here that its keeps on giving me 1 side of the mp3 or channle 

thanks a bunch 😄