This is the 6489th most frequent Swedish word.
mangnus
It seems "mangnus" is not a recognized Swedish word. Could you mean "Magnus"? If so, it's a male name derived from Latin meaning "great."
Mangnus is used here as a proper noun, referring to a person's name.
Mangnus är en kapabel snickare.
Mangnus is a capable carpenter.
Mangnus is the name of an individual being mentioned as the subject of this sentence.
Vi såg Mangnus på marknaden i morse.
We saw Mangnus at the market this morning.
The word Mangnus is once again used as a proper noun, representing a specific individual, the subject of the sentence.