On mac os, we'll be using the excellent CubicSDR cross-platform, open source software. For this tutorial we'll use release version 0.2.3 Head to the Downloads page to grab the latest version, or click this link to directly download 0.2.3
Once you've downloaded the installer (in this case named CubicSDR-0.2.3-Darwin.dmg), double-click it to mount the disk image, and then drag the CubicSDR.app to your Applications folder as shown here.
Now, plug your RTL-SDR dongle into a USB port on your mac, and then double-click the CubicSDR.app in your Applications folder to run it.
When you launch CubicSDR, it will pop up a window asking you to select and start your SDR device. Pick the one named Generic RTL2832U OEM :: 00000001 and then click Start.