Every resistor has the value of 1 Ohm.
So, the question here,first:
How can i calculate the resistance between point AB?
and then, second:
Resistance between point AC
The arrangement of the resistors is in the link below.
The answer to your problem is based on parallel and series resistance calculations. Here in the AAC ebook you can read up on these two important calculations.
Since this is a homework question it would be wrong of me to give an answer.
Try attaching voltages to the circuit and current paths it should be simple since the are all the same value. If you have the time you could build one and apply a voltage and mesure how it splits, it will indicate how the current flows, and will help you understand the circuit.