The only interaction necessary is to tap the screen as many times as you can. The more you tap, the more money you receive, and you want to make sure to get as many coins as possible to invest them in improving your new city. On the other hand, you also have to improve the effectiveness of each tap, so that everything you earn is managed as efficiently as possible.
Also in City Growing-Touch in the City are other upgradeable features to boost the constant development of buildings and other areas, like cost reduction for construction, for example. Use the auto clicker feature to get the most out of your taps and amass a fortune to help you build the best area in the entire city.