If I had my time again, I would start an electronic logbook from day one.
MCC pilot log is the one I now use, and it is excellent. You can print the pages off if you need something signed, and even send off the pdf to be made into a proper bound logbook if you needed it for an interview or something.
Just to actually answer your question, you log from the time the aircraft starts moving under its own power with the intention of taking off, until the time the aircraft stops after landing. No more, no less, so no pre-flight briefs or tie downs. Once you start learning your instructor will help you out, and show you what needs to be done.