Each of you will keep a bound lab book. This is a largely hand-written document that contains anything that is relevant to the project. It can contain your ideas, musings, etc., pasted drawings, just about anything. Keeping a personal lab book is standard procedure in industry. Note that the notebook is generally considered company property is is often turned into the company when you leave the company. However, the document is informal and some people just keep their lab books throughout their career. In any case, it is considered best practice to assume that you may want to share your lab-book with others and to write the content accordingly.