Ah, if you want to jump to an active frequency by clicking in the spectrum display, make sure you have the right mode selected (usb, AM, whatever) and also that the step size is correct. If the step size is too big, you will not be able to make the red line ‘land’ exactly where you want it. To select the correct step, right click within the frequency display and a drop-down menu of step sizes should appear. Click on the one that suits the mode.
Most modes should automatically select the correct step, but there used to be a bug that meant this didn’t always happen. I’m not sure if it’s been fixed or not.
BTW, you can find the operating manual for the receiver in the OPT menu in the small MAIN panel.