App: Offline routing (BRouter)

Sorry, I don’t understand what you mean. I don’t want to use another app as Kurviger (apart from Navigon Cruiser which I still have on my device). Graphhopper works offline when I download the graphs as described. You said Brouter would be more flexible offline. What do I need to use it as a fallback to Kurviger? Install the app, download maps or graphs? From where? I have checked all links and still didn’t find how it should work.