Play therapy is a time and place each week especially for you, where you will spend time with your play therapist doing whatever you choose to do. There will be lots of creative activities you can choose from, like clay, painting, music, role play, sand and messy play, as well as other things to play with if you want.
You might be coming to play therapy because adults in your life have noticed that you are not being your usual self, or they may be worried about how you are coping with a certain situation. You might be showing a lot of big emotions (maybe like sadness or anger) which might be making you feel muddled inside. In your play therapy sessions you do not have to talk about how you are feeling because that can be really difficult, but the sessions might help you to feel better anyway.
Your play therapist will have some meetings with certain adults in your life, but she will not tell anyone what you do in your play therapy sessions, unless she thinks she needs to tell someone something to keep you safe.