To use this TFT shield with an ethernet shield you should remove pins 50, 51, 52 and 53 to prevent conflict with SD card slot on TFT.
To use this TFT shield with an ethernet module you should remove the pin 53 then make a bridge to pin 4 like this:
Leaving the pin 53 on TFT shield and adding the bridge you are making a short circuit between pins 4 and 53 on Arduino.
RTC DS3231 module:
The connection should be:
+ to 5V
- to GND
D (SDA) to 20
C (SCL) to 21