Teaching technical English workshops

[Annabelle]

I'm teaching two classes of 8-10 adults (pre)intermediates for 90 min. I chose Tech Talk beginners to get us started. I'm trying to adjust the book because the grammar is too basic although they need the vocabulary. My issue is that I'm also giving them workshops. The HR department wants me to set up calls and do conference calling classes with non native English speakers from all over the world. I'm trying to figure out how to set up the structure of the workshop. I thought they could prepare a product presentation to give. I don't know how to prepare the "caller" who is not in the class or the students, or even the program. Help!

Thanks in advance,
Annabelle