Deductions & credits

Hello,

 

As an agent I only had one transaction last year. The brokerage sent my 1099 Misc showing my gross commission, but I don't know how to back that down to my AGI. The brokerage took 20% (of which I was obviously not paid). 

 

I was also part of a mentor program that took another 20%. 

Can you explain where/how to deduct this so I really only get taxed on money that I saw as income?

Thanks!