This is very simple.
To send or a new message from inside the app:
Go to the 4th tab - Chats. Tap on WiFi or Sim. WiFi lets you send a message to another TextApp user through his/her TextApp (WiFi) number for free. SMS lets you send a text to any user in the world using his/her real-world phone number (using ISD Code).
Tap the new message button at the bottom right on the screen.
Type in the contact number, or add a contact from the app contacts list by tapping the Contacts icon on the top right of the new message screen.
Just like any messaging app, type your message text to send.
To reply to a message from inside the app:
On the Chats screen, you will find a list of the sender(s) under Chat and SMS headings, select one you want to reply.
Tap on a sender to whom you want to reply.
Just like any messaging app, type your message text to send.
To receive a message from inside the app:
You don’t need to do any additional provision once you have the app with a number ready.
When a new message is received, it will display on the Chats screen. The message will appear under Chats if received on your WiFi number, and will appear under SMS, if received on your Private Number.
In case the app is not visible (open) on screen, you will get a notification when someone sends a message.