Lagers are not quite as simple as all that. You can't just follow a time table on every beer and be OK like you can with most ales. Some yeast strains don't produce any diacetyl so a d-rest isn't necessary, others do. In any case, a d-rest won't do you any good if you wait until primary fermentation is done. Some yeast produce diacetyl during fermentation (ales and lagers), ales are already warm enough, so before fermentation peters out, the yeast clean up after themselves and no special attention is needed by the brewer.
For a lager, the yeast can't clean up the diacetyl at lager fermentation temps, so you must raise it to 65-70 degrees for a period of 24 hours or so, near the end of fermentation. If you wait too long, the yeast will be asleep, and won't do jack to clean up after themselves, too early and you will get esters and fusel alcohols formed. When the yeast is about 75-80% of the way to final gravity is when you want to do a d-rest. You can kind of judge this after some experience by watching the krausen and airlock, but you really need a hydrometer. When you have reached near terminal gravity, let the temp of the beer self rise to around 65 and hold it there for a day. After the day, slowly (about 5 degrees per day) bring it back down to lager temps. I usually transfer to secondary when I have gotten back to my fermentation temps, and by then fermentation has completed. It also helps clear out some of the yeast waiting till it's cool again to transfer. Go to secondary, drop to lager temps, and wait.