For a frame of reference, traditional sprinklers should not run for more than 10 minutes at a time (on average). Why is this? After 10 minutes the water just runs off to the street. No need to spend your water and money watering the sidewalk! If you think your landscape needs more than 10 minutes, you can add more start times; but remember to space out the time so the water can be absorbed by the soil. Give it about two hours or more (this can vary depending on the soil type in your yard).
If you are intimidated about setting your sprinkler schedule, don’t worry! You can get an easy-to-understand summary of timers here: how to program your sprinkler timer.
When you are ready to schedule your timer, try doing an online search for your specific sprinkler timer. Look on the box for the brand name like “Rain Bird”, “Irritrol”, “Hunter”, “Orbit” or “Toro”. Once you have found the brand, look for the model number like “ESP-6MT”, “SlimDial”, “X-Core”, “SST-600i” or some other jumble of words and letters! Enter the brand name and model number into your search and you should get manuals as well as online tutorials showing you how to adjust your timer.