You are editing the details for this property:
The existing location of this property is shown by the blue icon on the map, and the current data has been pre-filled in the form. Just change the details which need changing, and click/tap 'Submit'
The most important information is the latitude and longitude of the property location. It is utterly essential that these are correct. Please do not submit the form until you are confident that you have got these right.
If you know the latitude and longitude (maybe from a separate GPS device), you can type them into the fields. But the easiest way to get them is to position the red marker on the map to the correct location. Just click/tap where the property is to set the details. Accuracy is important, so make sure you're zoomed all the way in first!