All work needs to be recorded accurately and clearly. When you join the lab you will be given a lab book. This book belongs to the laboratory, and is a permanent record of your work. Tim has recorded lectures on how to record research work in a physical lab book. If you have not viewed these then please ask to see them.
You should ask your supervisor to demonstrate good practice in recording entries in a lab book prior to starting your work.
Note that these lab books are a permanent legal record of the work you have undertaken. If your work is not recorded in your lab book then it has not taken place.