It depends on your current eating schedule, really. If you're used to eating whenever and always, it'll probably be pretty tough, both physically and psychologically. If you're used to structuring your mealtimes a bit more, or are already doing some form of IF, it'll be easier. But regardless, it'll be at least a few days (and a lot depends also on what you're eating -- if you're heavy on the refined carbs and processed foods you'll probably have a harder time since your insulin will spike more.)

Here are some tips:

• keep water/tea/coffee handy. stay hydrated. This will help a lot.
• Decide your eating window beforehand. Some people like to wait all day and have a big meal + snack in the evening. Some people like to eat around lunchtime. It depends on what you find works best for your body and your mind. I find eating earlier in the day helps me, since I don't have a lot of time to really feel deprived of food. Either it's the morning, and I'm not hungry anyway, or I ate earlier and I'm still pretty full. But it's harder if you're a social eater, as dinner is usually when people eat together.
• Decide what you'll eat beforehand, at least at the beginning. Make sure it's got a good mix of protein, healthy fats, and foods rich in micronutrients. I wouldn't worry so much about portions in the beginning -- just eat until you're full, and your appetite should eventually self regulate. If you don't feel deprived, you're a lot less likely to binge. Ending your eating period on something rich in protein/fat (think: cheese, nut butter, that kind of thing) will also help you stay fuller for longer.

Good luck!