Even if you’ve just started and there are a thousand things to do, don’t wait, just start. Scrum was designed to start a team in 2 days or less. Put everything that you feel you have to get done into stories and put them in the backlog. Even the task of making the backlog itself can be a backlog item! You only need enough stories to fill one Sprint, then while that one is going on, you develop more stories, and more, and you’re off and running.
One of the basic ideas of Scrum and Agile and Lean is to have the absolute minimum you need to enable the work to get done. If your set up is too complicated, you’ll have introduced waste into the system at the very beginning. Instead of thinking you have to have everything all set up and planned, just begin. Think of it like a worker on a line at a lean manufacturing plant. The guy who installs the spark plugs only needs eight sparkplugs in his work area at any one time, more is just waste. So how do you set it up with only the parts you need? Just build one Sprint of stories and begin.
If you want to learn how to begin, there are still some seats left for my Certified Scrum Master Course on July 26-27 in Boston.