You do not need to turn the solar panels on. They have blocking diodes that do that automatically, so that are always connected. Do be aware that if you ever need to disconnect things, for repair or to replace a battery or any other reason, you must disconnect the solar panels before you disconnect the charge controller. Reconnecting, you must connect the charge controller before you connect the solar panels.
If you put the rig in storage and use a battery disconnect switch to prevent discharge of the batteries, be sure to disconnect the panels before using that battery disconnect switch. Solar charge controllers can be damaged if connected to panels without already being connected to a battery.