Advice and Info on Non-Performing Notes

[Ethan Henning]

Hello all, 

I ran into a seller that has a whole bunch of nonperforming notes and I am staring at a spreadsheet with hundreds of different numbers and values. Does anyone have specific advice in terms of what to look for? Assessing value and what to keep an eye for. I have a general concept but I cannot pin down specific details in any info online. Any info would be greatly appreciated. 

Thanks!