Just like a 12 lead and the echo tech will let you know if they need to be moved when she does her rest echo.Make sure they are taped on there-artifact is inevitable but reducing it is the most important part.
Old post, so you have probably already figured it out...but RA, V1, V2 and LA go in a line high on the chest,following under the clavicles. RL is low under the ribs on the right. V3, V4, V5, V6 and LL go in a line low under the ribs as well. Just keep in mind that the echo tech will need access around the area of the heart, so do not place tape, leads, etc... in that area. People come in all shapes and sizes so if the tech needs to move them they will. If you follow these guidelines you should be fine though!