Setting up the emulator is pretty simple. In contrast to other emulators for Android, MegaN64 is really easy to use, so you can start playing without even touching the setup options. That said, if you want to you can customize the controls and adjust the different visual settings. By default the graphics are still quite good, but you can make them even better depending on which Android device you have.
MegaN64 is an excellent emulator. Apart from being completely free, it's not at all hard to use. If you feel like playing the 64-bit Nintendo classics, don't hesitate to give it a shot. Especially if you have a Bluetooth controller for your Android.