Hello Tanya2023, if you already uninstalled the app then automatically all files, including caches, associated with the uninstalled app is cleared. If, however, you want to clear caches on apps that are still installed all you have to do is tap and hold down on the app and select the "i" from the box that pops up and then click on "storage" and click on "clear cache" at the bottom of the screen. You also have the option to "clear cache partition" but this is a more technical and extreme method used when you've had your phone for a long time but since you said you've just gotten the phone there is no need for this, yet.
