If you have never given up sugar before, it will take at least 6-8 weeks of non-use before the cravings go away. These will be some of the hardest weeks too.
1) everything has sugar in it, and you have to absolutely avoid it, not just sweets, fruits, juices, I'd even tell you diet drinks and artificial sweeteners too. That means no ketchup, sauces, breads, and most processed and store bought foods.
2) your body will do everything to remind you about those easy access sugars. During your detox, you will have cravings, dreams about sweets, even the overwhelming urge to eat stuff you might not even thing about "oh god, i could really go for some prunes right now" sort of thing.
After your body gets it figured out that your no longer getting access to easy glucose it calms the hell down. You'll notice one day that sweets just don't seem that appealing. You'll get better at detecting sweetness in things you would have never considered sweet, like lettuce.
I warn you sugar is insidious and everywhere. One day, you will sit down to some mundane meal, nothing special about it. After a few bites, you will say, wow this is wonderful, its the best thing I have ever tasted, I absolutely must have more of this very mundane thing, I'll need seconds, thirds, more if available. That meal you were eating was loaded down with sugar, it probably didn't taste sweet but it will taste like the best thing ever. That's how sugar gets you.