A 1/3 superfree should be incorporated into every meal where possible. This helps control your carb and protein portions.
For snacks - your choice should be a superfree food first if you can, but of course your syns and HEb's are there to be used, so if you dont feel satisfied by just a superfree food, then you can use your syns etc.
It is recommended that you have a minimum of 5 syns a day. Syns are automatically controlled because the maximum is 15 a day.