Usually at the end of the namefile you download there is a symbol like “_3dh”, “_180”, “MKX_220”.
There was a recent comment on it from the Heresphere dev, so take a look:
https://discuss.eroscripts.com/t/heresphere-vr-video-player-for-quest-2-has-native-script-support-for-the-handy/57962/139?u=husky
Use your Quest controllers to move/rotate/zoom the image until you are comfortable with it. In Heresphere’s options you can find the keybindings.