Write questions, only questions. No need to answer them or explain much about them, just write questions. The only requirement about the questions, is that you not know the answer to them already.
Begin with your surroundings. Write down a question about the very first thing your eye chances upon. What does your glance happen upon next? Write down a question about that. Keep going until you fill the page.
If other questions come to mind, questions about things that aren’t in front of you, write them down, too.
When the page is full, draw a picture on it somewhere that shows the answer to one of your questions.
Be sure to give your work a title and write the date on it as well.
Here is a more detailed version of these directions.