Daylight savings time includes a shift in time one hour forward, and therefore the time at 2:00 AM will be switched to 3:00 AM.
Daylight savings time was introduced with the aim to make days during the summer, includes a part of spring and autumn, last longer. This was introduced because of the need to reduce electricity costs. Since the day is lasting longer, we have more natural light and we spend less electricity.
(Source: fokus.ba)