You will need four cards to create your own roller coaster ride; station, train, tracks, and chain lift. Cards can be obtained from packs which you can get by levelling up, completing missions, or buying them from the Card Shop. The cards you get in a pack are random so you may have to get several packs before you get the four types of cards that you need before you can start construction of your ride.
Once you have the required cards and ensured you have enough space you can begin by placing a basic set of tracks so that you give yourself a guide on where you are going to add the extras. Each node can be modified three ways; sliding the track around on the X and Y axes, changing the elevation of the track by moving it up or down, and twisting the track left or right to bank the turns. Once you have performed any or all of those options on a node you simply build out to the next one. If applicable, you can also tap the ‘Add Special’ icon to throw in a loop, spiral or other fancy track section, though there might be some prerequisites to doing so. All you need to remember when you build your roller coaster ride is that it must meet back at the beginning when it’s done.