How long is a piece of string?
When you start canvassing, each day will be different, and determined by a number of factors, ie how many doors you knock, how many people are home, how many are interested, etc. etc. Some days you may pick up a good few, other days nothing.
All you can do is go out and get knocking asap. The sooner you do, the sooner you will hit your target. Keep positive and be friendly and you will be OK.
Best wishes,
John