Okay kiddo, so a voyevoda was kind of like a boss guy in a big area of Russia a looong time ago. These big areas were called provinces and the voyevoda was in charge of making sure everyone followed the rules and didn't cause any trouble.
It was a very important job because the voyevoda was responsible for making sure the area was safe and that people had enough food to eat. Besides that, they also had to collect taxes from people so the government could use that money to help the whole country.
So imagine the voyevoda as somebody who is like the principal of a giant school called a province, and he has to look after all the students (people who live there) and make sure everything runs smoothly. Pretty cool, huh?