Some people do the lessons in different languages back to back, one right after the other. I've seen others designate certain times of the day (morning - language 1, afternoon - language 2, evening - language 3) or certain days of the week to each language (M, W, F - language 1, T, Th - language 2, Sa, Su - language 3).
I'm sure whatever you choose will be what's best for your family. I don't think you can really go wrong