We will only receive the inbound messages in the Conversation tab using Topline OS mobile app and web app.
Incoming SMS will not be forwarded to the forwarding number
You set up a Customer replied workflow trigger like this with the Custom Value {{message.body}}
Click on Automation > Workflows > Create workflow
Choose Start from scratch
Click on Create new workflow
Click on Add New Workflow Trigger
Click on Customer Replied
Click on Add filters
Select Reply channel
In the reply channel dropdown, choose SMS
Click on Save Trigger
Click on Add your first Action
Click on Send Internal Notification
Note: SMS notification will create charges for every SMS sent
Click on Custom Values > Message > Message Body
Click on Contact > First Name