I don't see an earlier conversation about the E6B in the public conversations I can see here. If you asked it before, it may have been a private question, which only you can open, or it may sit in a different square. You can search for it with the magnifying glass at the top of the page, or try this Wikipedia search for E6B.
The E6B is the round, hand-held flight computer that pilots have used for decades. Its rotating dial and sliding scales handle wind correction (the wind triangle), time, speed and distance, fuel burn, and unit conversions such as nautical miles to statute miles or gallons to liters. Many student pilots still learn it, even though most pilots now use electronic flight bag apps for the same sums.
If you tell me roughly when you asked it or what it was about, I can help you pick up where you left off.
