Utilitarianism is based on the principle of providing the "greatest good for the greatest number." Essentially, this means that a utilitarian will always choose the option which saves the most lives, or allows the greatest number of people to be happy. However, the person making the decision should not show bias towards themselves, their family or other loved ones as each individual involved should be taken into account equally, regardless of personal connection. For example, a true utilitarian would, given the option between saving from certain death ten members of their family or one hundred complete strangers, choose to save the strangers. Hope this helps!