To actually see what is happening on the development kit while the application is running, enable debugging in nRF Connect for Visual Studio Code. See Debugging an application for more information.

Complete the following steps to start debugging:

  1. Open your project in SEGGER Embedded Studio (SES).
  2. Build and program your application to the kit as described in Building and programming a sample application.
  3. Select Debug > Go.
    Alternatively, press F5.
    The debugging interface looks like this:
    Debugging interface
    By default, the application will break in main. You can set additional break points, single-step through the application, read registers, and so on.

This video tutorial shows you how to use SES for debugging:

YouTube tutorial