The Prophet Muhammad (PBUH) celebrated the very first Eid Day with his family, friends and relative in 624CE after the Jang-e-Badar. Jang-e-Badar was the war between Mecca and Medina and it took place in the month of Ramadan as well. Some people say that this religious festival is not connected to any sort of historical war. They think its a unique festival comes after the 30 or 29 days of Ramadan which is confirmed by sighting the Crescent Moon. Ramadan is a holly month of fasting of Muslims. Muslims say no to food, drink and all others bad activities from sun rise to sun set and devote themselves prayers to Allah and learn the self control. Muslims believe that its Allah's own month he close the doors of hell and open the doors of heaven for Muslims.
Muslims celebrate Eid Day in the same way throughout the world. They get up early morning and dressed nicely. Then they go to mosques and offered special Eid prayer. All attendants after prayer greet Eid Mubarak and embrace to each other with hug in the spirit of peace. Then they do get together between their family and friends in joyful atmosphere. Eid-ul-Fitar is a day of happiness and thanksgiving to Allah who give the opportunity to us to fulfil the obligations of fasting and good deeds during the month of Ramadan.
Muslim celebrates the Eid-ul-Fitar according to Islamic calendar, which is lunar calendar. Islamic calendar is 11 days smaller than Gregorian calendar, which is based on solar1. So that's why every year Eid comes 11 days early on Gregorian calendar. Eid vary from country to country as well because it depends upon the moon has been sighted or not. It is usually one or two day's difference. This year in Pakistan Eid-ul-Fitar is coming approximately on 2nd May - 2022.