We erect a chart based on the birth of a question - so the moment a new question is born in your mind. Note the time when a clear question forms in your mind and then use the date, time and your location to erect the chart. The questions have to be deep and meaningful for you, not for mere curiosity, questions that could change your life for better or for worse. Questions such as 'Will my usual hairdresser colour my hair tomorrow' is not a meaningful question. Question such as 'will I get into Engineering course at Uni' is a meaningful and life changing question.
If you still don't understand, do some research - look around and you'll see the questions people are asking, dates. times etc...
all the best!