Hello McEgg,
that depends on the date of the development plan. However, it looks like it is younger than 26 years, so the form posted by Bauexperte fits. With strict application of the Land Use Ordinance, it will be tight with your terrace, as it must be fully counted. If your planning from 8.2. is still current, I will make the following calculation:
540sqm*0.3=162sqm buildable area
House 10m*11m=110sqm
Garage 6m*6m=36sqm
leaves for the terrace 162sqm-110sqm-36sqm=16sqm
In practice, the terrace is often included in the so-called GRZII like the garage and driveways. These areas allow the maximum plot coverage to be exceeded by 50%. If you fully utilize your building window, it would be:
Terrace 10m*4m=40sqm
Garage driveway 5m*6m=30sqm
Access path to house 2m*3m=6sqm
(110+36+40+30+6)/540=0.41 < 0.45=0.3+0.5*0.3
So it would fit if the terrace is considered as an ancillary facility.