How to create an account ?
Messenger is part of Facebook services, so you need to create a Facebook account to get access to Messenger. Go to the Facebook home page, enter your first name, surname, mobile number or email address, password, birthday and gender and click "Create account".
A security code is sent to your email address or phone by text message : enter the code on the page, validate. You have now access to your own Facebook account.
If you want to secure your Facebook account more, you can also click on the top right arrow, go to “settings” and then “security and connexion”, then choose your settings to receive an alert everytime a new device connects to your account, choose friends to contact in case your account is stolen (they will be able to send you a restauration code), or get the 2-steps identification by text with your mobile number.