Color Correction — Where to begin?

[DÅ‚ugosz]

I've not needed it before, but the lighting must have been funny ââ,¬â€ different on subject than background.  I tried the various color filters that came with AVIDEMUX, but can't figure out what to do with the sliders to make it look right.  I looked for tips online and it shows displays like a radar screen and histograms, that are used by pros.  I wonder if there is a front-end that uses some display to help me choose settings, that I can then feed to one of the free filters?  Or, some other way to figure it out.