Message a person on your pa list
If you want to send a message to a pal, tap on the 'pal list' icon on the very top right of the screen (it looks like two people).

Your list of pals or 'pal list' will slide out from the right side of the screen.  Now tap on the nickname of the person you want to send the message to, then tap on 'send a message' on the menu that appears.

Touch the ‘message’ area at the bottom of the screen and enter your message using your device’s keyboard. You can use your standard emoji's when sending messages. If you want to include a sticker, click on the '(+)' icon to the left of the message area.

Tap ‘send’ on your device’s keyboard to send the message.  You can leave messages to your pals even if they are offline.  They will receive your message when they log in.

Message a person in a chat room

You can also tap on any user in a group participant list to initiate a message.

Open the participant list by clicking on the ‘people’ icon (it looks like two people) near the top right of the screen when in a chat room.  Now tap on any user name and then select ‘send a message’ from the menu that appears.

As above, type your message into the ‘message’ area and tap the send button on your keyboard to send your text.