I was a German as a Second Language teacher once. Theoretically, you start with very easy things, pointing at stuff, pictures, … and work your way up from there. Defacto, everyone spoke English so we had a common language. I’m pretty sure, people who live in an English speaking country know enough English to get along. Even at some point in school, teachers explained grammar and to an extend vocabulary in English even tho we all spoke German as a native language (including the teachers)