This tool is to manage the finder camera, it is visible only when a device is defined and selected in the Slewing preferences.

It is possible to start a preview loop to adjust the focus and exposure for the camera. Be careful to not let this loop active when using the same camera for autoguiding.
When the option is checked it is possible to save every images from this camera.

To work more precisely to center a target in the main instrument it need to be calibrated for the offset between the finder and main instrument.
You can enter manually the X,Y position of the main instrument in pixels or use the Image center button.

But for the maximal precision it is recommended to use the Finder Calibration tool.
Start by pointing the main instrument at an easy to find target, for example a bright star. Be sure it centered at the exact location you want, for example on the spectrograph slit. Note the J2000 coordinates of this star.
Click the button Calibration measurement.

Enter the J2000 coordinates you note before, really the coordinate of the star, never use telescope coordinates here. You can past them from the clipboard, or plate solve the main camera image if this is possible.

Click the button OK, it take an image, plate solve, and compute the offset automatically.

The result is a green cross indicating the center position of the main instrument.

It is possible the cross do not show if the offset is larger than the finder image size. This not affect the precision if not too wrong but you may want to adjust the finder mechanical pointing to reduce the offset.

You are now ready to point any target in the main instrument from a sequence or using the mount Goto tool.