I. Target app (or client app)
In order to track all activities of one device, you must install directly the application on that.
So far and in near the future, the application is available on Android OS (Samsung, HTC, Oppo...) and iOS (iPhone, iPad).
That means it depends on what OS of the target device, you should install a compatible version of the OS.
1. For example, your boy is using an iPhone, you must install the application on iOS:
You must jailbreak the iPhone. After jailbreaking, you will see an application named Cydia. After launching the Cydia application, you will add a specific source on that and then you will install the application on that iPhone.
Here is the link for detail how to install the application on the iOS device:
Of course, you can hide the icon of the application and start to track all the activities of the device immediately.
2. If your girl is using a Samsung device for example - it is Android OS, you must install the application on Android. That is an APK file and you must download to the target device and then install it.
It is no need to root the device, but in case you want to track 3rd third-party applications (social networking applications), you should root the device.
Otherwise, no need to root. You can track basic feature such as GPS, SMS, Call History ...
Here is the link for detail how to install the application on Android device:
II. Website of the user control panel
This is a website of the user control panel. It is secure and only you can access it with your username and password.
When you install the client app (target app) on the device, the data logs will be sent to the user control panel. You can log in with username and password to view it, or can download/export it to your PC/laptop.
The user control panel site is: https://my.thetruthspy.com
You can create/register an account here, or you can register in an interface of target app.
III. Monitor App (or Server app)
The monitor app (server app) is for you (parent) and target app (client app) is for your child.
The "server app" is the same meaning to the user control panel (https://my.thetruthspy.com). It is not a website but it is an application and available for both iOS and Android.
You can install the target application on your boy 's device with iOS version but you can install the "monitor app" on your Android device, or vice versa, you can track an Android device but use a "monitor app" on iPhone.
It depends what you device you are using.
Here is for 'monitor app' on Android: http://android.thetruthspy.com/monitorapp
Here is step by step for download 'monitor app' on iOS: http://iphone.thetruthspy.com