[mesmark]

I too agree you should start with example in their own lives. I generally start with yes/no questions 'Did you ~, yesterday?' Bring along a calendar, so you can expalin the idea 'yesterday' and then elicit from them either 'Yes.' or 'No.'

Once they have the question and simple answer down, plus exposure to a handful of verbs, then I'd start to form some sentences in the past.

I like to start with 'watch TV' because most people watch TV :P

I always model the example answer 'I watched the news.' and then elicit some answers.

My suggestion is to build some vocabulary and confidence. Don't go too fast and have a good time!