Messenger allows one to send a message to selected number of members by clicking on the icon next to your profile picture in the upper right of the page.
Next click on the create new talk icon at the top of box on the left.
At the top of the box on the right start typing the members name and click on member name for each entry.
Entering a single member will bring up message history or if a group will bring up group messages. When done selecting members click on the word message... at the bottom of the box and type in you message.
The three icons allow adding: emoji, send recorded video, and files(picture, pdf, etc.) Hit Return when finished to send message. Past messages options are accessed by the the circle with 3 dots at the right.
If you see connecting.... there is a lost in connection with the messenger server. Check your internet connection. If it is good there is a server error or high traffic delay, try back later.