The directions differ depending on what kind of artichokes are used. I use the ones in the deli section that are usually floating in oil or water. These are already cooked and can be added to the saute just long enough to be warmed. They taste just as good as the others and make the recipe very fast to prepare.
Some grocery stores sell canned artichoke hearts and some come in glass jars. My experience with the canned version is that they all taste like metal. The ones in the glass jars taste good enough but are harder to find.
If you are using fresh artichokes you'll need to follow the usual procedure of steaming them, then cutting them down to the heart then quartering them before adding to the pan.