Simply put, displacement is how far you've been displaced from your starting location. say you start at 0. You now travel E (assuming East) at 10 m/s for 10 s. Now, let's assume m is meters and s is seconds. you moved east at 10 meters per second for 10 seconds. This means that for each second you moved east, you moved 10 meters. Therefore, your displacement is 100 meters because 10 times 10 is 100. So you would write 100m as your displacement.
