Single hotspot mode is a special mode of operation in which you will only have one hotspot. In this mode you usually just open the sidebar and swipe left and right over the sidebar to switch plugins. You can also switch plugins by using the plugin switcher on top using the plugin switcher.
When operating in single hotspot mode all plugins are opened using the same hotspot. When you are not using single hotspot mode, you can still switch plugins like this. The only difference is you'll have a hotspot for each plugin. If you don't have any plugins, you can switch to single hotspot mode, without noticing any difference. Only when you use gestures you'll notice the difference.
When you try to set up gestures, Appsi will tell you you are not in single hotspot mode. It can take you to the hotspot settings screen, from there it is easy to set up the gestures.
(hotspot location screen)
In this screen you can rearrange the hotspots with a long press, put when you tap a hotspot it will show a popup with additional settings. Tap the settings icon on the popup
(hotspot settings popup)
When you press the settings icon you will go to the gesture settings for that plugin. In a future version this will be simplified to one gesture settings screen. For now this is the only way to go there.