This is the messages "Inbox" for the EtereWeb station, where all the received messages are stored for the current login user.
User message
At the top right corner, the number in green indicates the total number of message count in the Inbox, one message per count.
After reading the message, you can reply to the sender by selecting the message-based date and time and clicking the "Reply" button to lunch the new message creation dialogue.
Create New Message
When you have compiled the reply, click the button to send the reply messages to the sender and all recipients.