Use the low output since that tracks best when feeding pitch cv into the v/8. That’s about it for a sine ping.
Pinging allows you to play the Three Sisters as an self contained oscillator without needing a VCA to lower and raise the volume. It is primitive if just using a gate into it. Nicola Ratti made a whole album pinging filters though.
If you just want to feed a sine into a Mangrove input, turn Quality all the way up and use the Low output if you’re using pitch cv into the Three Sisters.
I’ve had Three Sisters for several years and I’m still finding new things. You don’t have to use it as just a filter or oscillator, but it can be either.