1. download the app.
2. create the wallet.
3. save your wallet address.
4. save private key/seed. (on your dairy or print it.)
5. possible to convert QR on key/seed. (then print)
6. When you run out of needs. Then uninstall the wallet app.
Downloading the software from official site or google play etc aren't always 100% safe, you need to verify the signature.
When you want to print your private key/seed phrase, you need to know if
printers might store your private key/seed phrase. Similar to converting your private key/seedphrase, you're need to use tools and they might compromise your wallet.
Uninstalling the wallet from your phone aren't necessary means your cell phone completely delete every data about the wallet.