Have you sucessfully upload anything to the Arduino yet?
Clearly you are going to have to solder some wires to the connectors on the back of the display. Use 4 different colours, ideally red to Vcc, black to Gnd, 2 other colours to sda and scl. Then connect them to +5V, 0V, sda and scl either directly to the Arduino connectors or via your breadboard. Its usual with i2c bus to have a pair of pull-up resistors on sda and scl, but on Uno you can sometimes get away without them.
Then try uploading the sketch you were given for the display. If the sketch uploads ok and nothing happens, try connecting via the breadboard and use your 3K3 as pull-ups.
You cant connect the temp sensors direct to the Arduino because you need to form a voltage divider with a 10K resistor. Have another look at that link you posted earlier to remind yourself.
But concentrate on the display first.
This page tells you which outputs do which jobs on the uno
You will be using the Analog pins for the thermistors, pwm pins for the fans and the i2c bus is referred to as the twi bus on that page.