[MST3Kakalina]

It would probably be a bit more helpful if you described what you were already doing.

I taught this age group for a couple years and things that worked well were:

splitting classes into teams and earning points

individual students earning stickers, fake currency, or stamps they could later trade in for cool stuff (i've done this on a class-wide level as well as school-wide. it's easier when the school will support you in this, but it's possible to manage it yourself.)

not taking their apathy personally (some are only there because they have to be---that's okay, not everyone has to love every subject in school) but not allowing them to become a distraction

punctuating long classes with short "brain breaks" or easy review games (Hangman, pictionary, taboo, charades, correcting sentences on the board)

I don't know anything about keeping them "quiet and working" specifically. Language classes at that level go better if they're more interactive rather than "fill in this worksheet" etc. IMO.