You can connect an external account to your SyneMind account in two ways.
If you are not logged in, navigate to the Login / Register page (there is a link in the top right corner) and select an option from the available providers, for example Facebook. This will take you to a page on the provider's site, where you will be asked to log in and give permission to SyneMind to access your account. Note that at not point will SyneMind have access to your credentials (e.g. username and password) for the provider. Once you have given permission, you will be redirected back to SyneMind, where a new account will be created for you if you did not previously have one, or the provider will be connected to your existing account if you had one previously. In order to "connect" (identify) accounts, SyneMind uses the email address that you have on the provider's site and matches it to SyneMind accounts.
If you are already logged in, navigate to the Accounts and Profile section of your personal homepage, then in "Account" click on "Connected Accounts". You will see a list of available platforms with which you can connect, each with a connection status - connected or not connected. Click on the "Connect" button next to the platform you want to connect to. This will send you to a page on the provider's site, where you will be asked to give permission to SyneMind to access your account. After you do that, you will be redirected back to SyneMind, where the provider should now show with a "Connected" status.
When you connect a social account, what happens "under the hood" is the following:
The provider records that you have given SyneMind permission to access your account.
This permission is very limited and requires further actions on your part to allow more interaction.
SyneMind receives some (very limited) information about you. In the case of Facebook, this is your name, your email address, and a link to the thumbnail of your profile image (but no link to the actual profile).
SyneMind also receives an "access token" to facilitate interacting with the platform on your behalf. This is short-lived (typically 30 minutes) and needs to be renewed for later interactions.
SyneMind may use some of the information to populate your account - for example, name and email. Note that Facebook does not guarantee that the email is verified, so SyneMind will consider it unverified until it checks it independently.