Please be aware that for those of us using the mobile app, this type of link will boot us out of the lesson we are in and back to Duo's main page. We will not see the info and will lose the lesson we've been working on.
PLEASE don't ask me how I know this or... how many times I've... done this...
What Allintolearning said is correct. When you ask my mother what her Irish connection is, she says, "My dad's people came from Tipperary." "Muintir" would be the "people" in that sentence.
"Clann" can include grandchildren (and, presumably, great-grandchildren). Think of it as "descendants" (or, possibly more accurately, "descendants which you actually live to see").
"Teaghlach" would be "household" or "immediate family" (I would use it to include my grandparents who lived up the street and whom I saw every day, even though they weren't technically in my "household" growing up).