How do you build a parking lot on shop empire 2?

I struggled with this but eventually figured it out. First click the 'extra' button on the left side tool bar. On the box that pops up there is the option of adding 'Basement lvl 1' click this and add it to your mall. Once you have added this go back to the tool bar on the side. Click 'facilities' and you will now have the option to add a parking lot to your mall. Hope this helped :) :) :)