[sueby]

If they're absolute beginners, the best thing to start off with is name, tel numbers(to practise numbers 1-10), nationality, profession and 'How are you?'
You'll need flashcards of flags and professions (we even use smiley faces for How are you?)
Don't rush them and keep repeating everything you've introduced in different ways.
Model what you want them to say, they repeat and practise in pairs then move on to the next thing. Each piece should take 10-15 minutes. We use different games with the flashcards once the language has been introduced (students have to guess what the card is by asking each other questions eg.: Are you from England? No, I'm not. etc.).
I would suggest building up towards a dialogue that they could practise at the end of the class for them to feel that they have achieved something.

Good luck in your first class.