How do I create a 50 ohms Impedence Trace

Recently designing a PCB board that has four layers, am using SIM7020E chip from SIMCOM, a cellular Chip. The Datasheet said i should Use a 50 ohms trace line on my PCB for the antenna Pin side in order to match the circuit. What will i do to get 50 ohms trace value for the four layers board. Are there any tools or steps needed to take ?