Apps are little helpers that live on your phone. Getting them from the official store keeps you safe. The store helps you spot the real app. 'Free to download' is safe and costs no money. You can always say no to anything that costs money.

Hi, it is Buddy. Getting an app is easy. We will go slow together. You will not be charged to download. A step may ask for a password or your face. That is normal. I will tell you when to expect it.

Let us go through this together, one little step at a time.
Tap each step once you have done it. This is just for you. Nothing is timed, and nothing can go wrong.

If the button says Get or Install with no price, it is free. If you see a price with a dollar sign, that one costs money. You can skip it and look for a free one. Some free apps may ask if you want to pay for extras. You can always tap No or Not Now. Buttons may look a little different on your phone. The idea is still the same.
Only get apps from the official store. Get or Install with no price means free to download. It is fine to say no to any offer that costs money. To download, your phone must be signed in to a free account. That is an Apple Account on iPhone or a Google Account on Android. Your phone may ask you to confirm. If any part feels stuck, a helper at your local library can sit with you.