Signing in to Partners is email and password. The parts worth knowing are the keep-signed-in switch and what the app does when a sign-in is refused.
Open the sign-in screen
It is the first thing Partners shows when no session is stored. Enter the email and password you registered with.
Decide whether to stay signed in
With keep-signed-in on, closing the app completely and reopening takes you straight back in. With it off you are asked again.
You can also change this later in Settings.
Forgot your password? Tap the link
Enter the email on your account and send. Partners confirms the email has gone out.
Set the new password from the email
The link opens a web page where you type the new password twice. That page belongs to Davinote's website, not the app, and it tells you if the link has expired or the two do not match.
Come back and sign in
Return to Partners and sign in with the new password. The old one stops working.
Sign out from your profile
The sign-out option is in your profile. After signing out, closing and reopening the app brings you back to the sign-in screen rather than straight into the app.