To activate a trial version:

1. On the main screen of the app, tap Real-Time Protection.
2. Swipe left to the last screen and tap Try for free.

3. The trial version has been activated. Tap OK.

Upon expiration of the trial period, you can either activate a commercial version or the app will automatically switch back to the free version with limited functionality. 

To activate the paid version:

1. On the main screen of the app, tap Real-Time Protection → Get all features.

2. Tap I have an activation code.
3. Enter the code and tap Continue. If you are renewing the license, select the check box I have an old activation code.

4. Enter the old activation code to get a discount and tap Renew.
5. Tap OK.

To add an activation code and activate the commercial version of Kaspersky Internet Security for Android from My Kaspersky:

1. Sign in to your account on My Kaspersky.
2. Go to the Licenses tab.
3. In the Add activation code section, enter the activation code for Kaspersky Internet Security for Android and click Add code.

4. Select the license you have added and click Add to a device.
   

5. Click Activate application.
   

6. Click Close.