Obviously one of the first things a beginner needs to learn is the position of the notes on the piano. I ask the pupil to tell me about the sets of black keys and from there they start to learn where the notes are on the piano in relation to the black keys. For example, D is the (white) note in between the 2 black keys or B is the (white) note at the top/high end of the 3 black keys. (You will need to spend time with the pupil establishing the location of higher notes versus lower notes and the direction one must travel from low to high or high to low).
To help reinforce the learning of the position of the notes, I use finger puppets that start with one of the letters of the musical alphabet. These can be used in a variety of ways - making rainbows whilst flying/jumping/leaping (use your imagination) from high to low or low to high visiting the appropriate keys on the way, or finding for example, the note a second above the letter name of the finger puppet they are using.