The commission is in account currency per contract - in that case, 2 cents per contract. For stocks this is normally a approximation, since the real commission is often more complex, dependent on the country and with a maximum and minimum per order, such as 1$. You must check the commission on the broker's website and enter a value that best fits your backtests. All parameters in the asset list are described in the manual under "Import".

If you want to get the commission accurately, enter 0 here and calculate it individually prior to every order.