Samsung Galaxy Grand supports two SIM Cards, and you set different notification tones (call or message) for each SIM. To change ringtone on Galaxy Grand do as follows:
1. Open "Settings" App and select "Sound" (There is a faster way to access Sound, which is: Drag down to notification panel, then tap and hold the sound icon)
2. Tap "Ringtone"
3. There are two tabs: SIM 1, SIM 2. Select the SIM you want to customize tone
4. Now change tone for incoming calls and notifications