The Ethiopian calendar is a way of keeping track of time in Ethiopia. It's kind of like a big, long list of all the days, months, and years that have passed. But instead of starting at "1" like most calendars, the Ethiopian calendar starts at "1" on a different day than most calendars.
In the Ethiopian calendar, a year is made up of 365 days, just like in the Gregorian calendar (which is the one most people in the world use). However, there's an extra day every four years, just like in the Gregorian calendar. This is called a leap year.
One big difference between the Ethiopian calendar and the Gregorian calendar is the starting point. The Ethiopian calendar starts on September 11th (or September 12th in a leap year), while the Gregorian calendar starts on January 1st. So if you're using the Ethiopian calendar, you need to remember that you're always a few months ahead of most other people in the world!
Another difference is that the months in the Ethiopian calendar are named after saints instead of numbers. There are twelve months in the Ethiopian calendar, just like in the Gregorian calendar, but they have different names. Each month has either 30 days or 31 days, except for the last month, which always has 5 or 6 days.
Overall, the Ethiopian calendar is like any other way of keeping track of time, but with some different names and a different starting point. It's important to remember these differences if you're working or living in Ethiopia, but in most other parts of the world, the Gregorian calendar is used more often.