Tutorial how to calculate commission fee for 3 layers/3 tiers upline in Multi Level Marketing

how to calculate rewards for Multi Level Marketing Transaction

There are 3 layers/tiers commision fee

1st layer Upline will get commision 10%
2st layer Upline will get commision 5%
3rd layer Upline will get commision 2%

How to design database and calculate algorith for this case ?
let me show you in this tutorial source code
There are 3 kind of files : php, mysql script, explanation in text file