To send a message you will first of all need to ensure you are on the dashboard.
Once on the dashboard, expand the "Send a message" drop down.
A message sent through Social Sense can be sent to multiple Social Media Accounts, even across different Social Media Accounts. To select the different accounts, simply click on the row of the account (as shown below) and it will be highlighted grey once selected. To deselect an account, click on it again and it will remove it.
Type your message (ensuring it stays within the 140 character limit if it is being sent by Twitter). The character limit can be seen below the content box on the bottom left hand corner and will show you how many characters you have left for each social media platform. Use the attachments button on the bottom right of the send message box if you wish to add an image or video. Click send when you are happy with the message.
If adding attachments then you can add multiple. However this must be within Twitter & Facebook's guidelines. You can only post one video to Twitter at a time but up to 4 images. To add multiple attachments, keep clicking "add attachments" for each attachment you wish to add.