Trading fees in broker application

How do we set up Pro Quant to account for the trading fees in broker applications? I am using Coin Base Pro. I think they take from profit of saling and stop the saling process.

If I have $400. Do I set it to 99% so when sale Coin base Pro be able to take out their 50 cents or whatever.

What I do so coin base takes the $0.50. And I take $399.50 from profit???