You can do it, but you need to be there to supervise. You can also check with Walter Andersen nursery and see if they will draw up a design for you for free if you buy their plants. Warning, their plants are expensive. I think the key is you being there and how much English the crew speaks, so they actually do what you want them to.
I would also make sure the part you want the sod on is fully prepped and that you get the weeds out first. We have had good results using Preen, but you should talk to the sod installer. I like it better than round up because it allows planting. It is a pre-emergent plant killer that will not harm the existing plants you want to grow. Good luck with the project and keep us posted.