Have they done French for 2 years already? When I taught it we started with Hello my name is... how are you... type conversations. Then numbers, days of week, months of year, colours, animals. Didnt really get much further than that. For a first lesson I would ask them to tell YOU what they already know and you can take it from there. Maybe have a song ready to teach them, you should be able to find heads shoulders knees and toes somewhere on the internet.