Fluxxo

Hi folks, just purchased the Islander 2 and love it. I've flown quite a time now. but I am always getting confused about the HSI. I usually ignore the GPS and fly oldschool by flying a track with WCA, VOR and ADF navigation. I tune in the frequency of the VOR in the GNS430 and activate. Now I can switch three sources/modes. Can somebody explain to me what these mean? Only source 1 will allow me to fly the VOR and moves the needle correctly. Would apprecate any help with this, as I am a bit confused. Thanks, Jan