Kārlis Johansons is a person. He has a name just like you do. Some people have different names, like how some people are named Emily or Sam.
Kārlis might live in a house, just like you do, and he might have a family and friends too.
Sometimes people use a person's full name, like Kārlis Johansons, to make sure they know exactly which person they are talking about.
That's pretty much all there is to explain about Kārlis Johansons – he's just a person with a name.