Here is a 'simple' diagram of all the sensors.
The 3.2" TFT fits on top of the mega. But you only need to connect pins 2-6 for the touch, 22 - 41 for the display & connect GND, VCC and 3.3V
Then for the SD card...you can use pin 50 --> MISO, 51 --> MOSI, 52 --> SCK, 53 --> CS.
The RTC module...SDA --> pin 20, SCL --> pin 21
The four channel relay is pretty self explanatory 
Without the cables attached..
And with...
Greetings...