Fitting games of true scale onto mobile is a difficult task. With complex strategy games reduced to a selection of menus thanks to the mobile's limited controls and screen size, the end result is often less than appealing. Massive-game-of-the-moment Spore Origins got around this by including about a fifth of the content of the PC original, but SimCity Metropolis tries its best to recreate as much of the city-building original game as possible.
As such, it's your job to build a city pretty much from scratch. Your city already has roads, so you only have to place the buildings themselves. These are split into three main categories. There are residential buildings to house your residents, industrial buildings for them to work in and amenities to make your city a nicer place to be.
Each building affects several of the stats that your city is judged by. These are things like the happiness of your citizens, the amount of jobs available, whether there's enough power to keep the lights on, and how productive the city is in industry terms. Big grim buildings that supply your population with jobs are likely to cause a dip in happiness while leafy parks will keep them happy and make the place look nice, but won't contribute much more.