The COOLPIX S3500 has a Scene Auto Selector mode in which the camera automatically selects the optimimum Scene Mode and adjusts the settings for you. This is a good choice if you want to just set the camera to a single setting and let the camera take care of the decision making.
If you want to choose the scene modes on your own, the proper mode is going to depend on what you are shooting as well as whether you are indoors or outdoors. For example, you may use Portrait Mode, Sports Mode or Landscape Mode outdoors depending on your subject. Party/Indoor mode is a good standard for indoor pictures, but Museum Mode and Backlighting are also suitable for shooting indoors.
You can find descriptions of each scene mode starting on page 41 of the S3500 manual. A copy of the manual can be downloaded from this address:https://support.nikonusa.com/app/an...