Skip three spaces, take note of something new, and write a line or two about it. Continue that way, skipping three spaces between each item until you reach the bottom of the page.
Return to the top. After each thought you have recorded about the present, fill up the empty space with some details from the past.
When the page is full, reread what you have written. Give your work a title and write the date on it.
Here is a more detailed version of these directions.