One night is from 8 PM to 7 AM (11h), the next one is from 8PM to 630AM (1030h). 2 teams come to deal with 17 sectors.
1h rest before midnight, then some go to sleep when sectors collapse. 6 ATCOs remain to deal with 3 sectors until 0330AM(ish), when they are replaced by 6 other ATCOs.
Then, the ones who sleep are called when needed to open sectors, most of the time in regard of the morning's oceanic traffic load.
The rest times are mostly under supervisor's responsability. They must be at least 33% of the time during night shifts (25% during day shifts).