To add freeform parking, click on the "Manual" tab under the garage adding section. Your view will switch to 2D, and the same set of tools used for drawing building footprints will appear, allowing you to draw the freeform garage.
If you know the exact number of parking spots you aim to generate, enter this number in the input field on the left side. This will display the approximate size of the garage that needs to be drawn. Once you have drawn the form, add it to the left-side card, similar to adding a building footprint. Remember to save the entire process to exit edit mode.