Above you have the option to adjust the balancing of your vessels.
A higher load equals a higher income, but also a higher fuel consumption.
It can be an advantage to adjust the load balancing if the current bunker fuel prices are high, thus saving fuel on your routes.
Once you have made your changes, hit Save Changes and navigate to Routes -> Depart vessel
Welcome to Shipping manager
Remember that you can get more help from the FAQ or at the Boards