To see a bit about how to use it (the grammar point), go to this link.
If you want to do some practice, here you are some:
We also did an exercise with the structure: TO HAVE/GET SOMEONE TO DO SOMETHING. In this case you have the person who is going to do the service, so the structure changes as it is not a passive any more; this link leads you to a blog entry which explains this: click here. Here you are an exercise to do: click here. Pay attention to the infinitive which can be with TO or without it.
Then compare the previous exercise with this one. You'll see that it's not you who did the action but somebody else; however, you don't know or don't care who was exactly the one who did it.
Hope it's useful. See you in class