A colleague of yours has set up a Sinch Contact application and invited you as a user. Follow the link you have received in the invitation email and sign in using the user name and temporary password. You will be requested to change your password at first log-in. It is a good idea to bookmark the sign-in page.
If you have not received an email invitation yet, ask your colleague who has created the Sinch Contact application to invite you. If a Sinch Contact application has not been created yet, join our early-access program and create one.