Track recording feature is available only in GPX Viewer PRO. So this how to won't work in free version of GPX Viewer.

Below are steps describing how to record and export track in GPX Viewer PRO:

1. First off you need to start GPX Viewer PRO.
2. Open left main menu and tap on Track recording button. This will show red recording button in the middle of right edge of GPX Viewer PRO screen.