is there anyone who can help me with a 5.1 project

I have 2 Camel Nearfest audio Footage.

1 From The Soundboard

1 From Audience

My Idea Was to make a 5.1 Mix with SBD in the front and Audience in the back.

only there are 2 problems all the files i have are Mp3 no flac and the second problem is that if you put it underneath each other it goes out of sync.

Would be nice for here on yeeshkul.

so if anyone is intrested in it please let me know