Need user friendly mixer interface

I need to hire a programmer to design a very simple user interface with Audacity/Mixxx or other open source mixing software.

I would like a simple mixer interface.

The Design would have 20 "beat tracks" of 5 min each imbedded in the mixer.

So a user could open the software and drop in their own spoken tracks (podcasts or sermons)
and then use a slide to set the "beat tracks" beat per min and also a slide to set the "beat tracks"
% volume of the output.

I am trying to build an easy mixer for myself so that I can keep a steady beat in the background as
I workout or job while listening to a podcast or sermon.