Using the dampers to control weight transfer under acceleration and braking is very effective and while they can be confusing, understanding how the damper settings work is valuable knowledge when it comes to setting up a car.
Dampers themselves are canisters of pressurized fluid that is forced through vales, orifices, or other small openings when the vehicle's suspension pushes or pulls on them. Unlike springs, the dampers exert a resistive force against the suspension depending on the velocity at which it is moving and not it's displacement. This force is generated because the fluid in the canister can only pass through the opening so quickly.
In the mechanics of Gran Turismo Sport, dampers are adjustable via. 10 settings in both compression (bump) and extension (rebound) on the front and rear axles. A the lowest attributes to the weakest resistance (large opening for canister fluid) and the highest value attributes to the most resistance (small opening for canister fluid). Compression, or bump, is when the vehicle's suspension bears more weight than what it was previously, Extension, or rebound, is just the opposite with weight being lifted off of the suspension.
Thinking in practical terms now, when a vehicle is under braking, weight is shifting from the rear of the vehicle to the front. As a result, the rear suspension is experiencing extension and the front suspension is experiencing compression. If you want to stabilize the weight transfer under braking, making the weight transfer happen slowly, then you would want to have a lot of resistance on the front suspension in bump, and/or a lot of resistance on the rear suspension in rebound. Conversely, if you want to stabilize the weight transfer under acceleration, the opposite it true since the rear suspension is in bump and the front is in rebound relative to just before power was applied.
The exact optimal balance varies from car to car and from circuit to circuit, as the damper settings also have a profound effect on cornering balance. Hopefully my explanation makes it a little more clear and allows you to experiment a little bit. If there are any questions please feel free to ask.
