"Expose for the shadows" means take a meter reading of the darkest shadow that you want to have detail in the final print, and close down about two stops.(posted 9252 days ago)"Develop for the highlights" means take a meter reading of the brightest highlight in the scene, and note how many stops this is away from the shadow reading. If this number is large, you will want to reduce the film development. Conversely, if this is small, then increase the film development.
(Your next question might be, "What is small, what is large?" The answer depends on the film, developer, enlarger and paper. This is why zone books are rather complicated.)
If you only overexpose by a stop or two, then don't worry about it. If the overexposure is much greater, then you may get better results by reducing the film development, but it depends on the film.