This ethernet shield is very easy to use, relevant libraries are provided. You can start your ethernet network in seconds.
Check the ENC28J60 module here which is only $7.9! and then connect it to your arduino as follow pinout
You probably only need VCC, GND, SCK – 13, SO – 12, SI -11, CS – 10 these 6 pins.
and then also connect ds18b20 sensor to your Arduino as follow
Please be aware blue wire are connected to pin 3 as declare in the code, DS18b20 sensor and Ethernet module can use same VCC and GND.
At last, download these codes and use them.
There are some another examples.