If you've just downloaded the app you'll be presented with our Welcome screen.
Tap the "Sign In" button if you already have an account with us or else use the "Create Account" button to create a new one.
You'll be taken to the Sign In screen. Input your credentials here or use the "Continue with Google" button to sign in with a Google account.
To sign out go to the "Profile" tab, scroll down a bit and at the bottom tap on "Sign Out". You can also "Sign Out All Other Devices" to end your sessions in all the other iOS devices in which you might have logged in before.
To sign back in, go to the "Profile" tab and tap on the "Sign In Or Create Account" button.