Ensure that the grape juice is not chilled, and you keep it at room temperature only. If the grape juice is in the fridge, keep them out for at least four to five hours outside the refrigerator.
Now, pour half of the grapes into the empty bottle and add one teaspoon of wine yeast to it. Shake the mixture, and then leave the bottle in a warm place for the rest of the day.
Now, prepare the sugar syrup by pouring the sugar into the empty coke bottle. You can make use of the plastic funnel for doing so.
Also, pour boiled water into the sugar until your bottle is half full. Shake the bottle properly but remember not to add the wine yet.
By now, your wine would have fermented well. You can add grape juice and sugar syrup to the five-liter bottle.
In ten days, your wine will be ready.