Before you can use Text Assist for 5250, you need to ensure that OfficeVision/400 Text Assist is available on your host, and Extra! is setup correctly.
Local Workstation
On your PC, ensure that you:
Select the Enable Word Processing (Text Assist) option when you configured your session. You can select this option for an existing session, but you will need to exit and reconnect the session before you can use Text Assist for 5250.