Why is the Chinese calendar different from normal,also want to know more about the Chinese calendar

Because Chinese calendar is based on lunar calendar and according to the movement of the moon. The normal calendar used now is based on the solar calendar.

The Chinese New Year is calculated using the Chinese Calendar, which combines multiple elements. The main feature of the Chinese New Year calendar is that it is a UNISOLAR calendar, which combines both the SOLAR (阳历) and LUNAR (阴历) calendars. In addition, it takes into account 24 JIEQI (二十四节气), which are based on China's geography, latitude, weather conditions, and other factors. There are also a few other elements that are considered in the calculation. Therefore, referring to it simply as the Lunar New Year by some media outlets is inaccurate.