Open the lid of the piano by pulling up on the corner of the lid nearest the top end of the keyboard. Use the stick inside the piano to hold the piano lid open completely.
Find the hammers on the inside of the piano. Hammers are made of wood and felt, look like miniature hammers and appear in a row, with most models having 88 hammers.
Look at the keys of the piano. If the keys of the piano are above or at the same level as the hammers, then the piano is a spinet piano. If the keys of the piano are well below the hammers, then you have a traditional piano.