Hi,
For the multicore debugging, you need to already have a debug session running under the main core (we will assume M7_0). This is started as a normal debug session, which is similar to the one provided on the available examples (we will use the Siul2_Dio_ToggleLed_S32G274A_M7 example) with a different script, as shown below:

We use the "all_cores" script, to initialize the cores on the platform. Then, under the secondary core (we will assume M7_1), we modify the debug session to be as follows:

With this, we are able to see that both cores toggle the configured pin on their corresponding side:

We are showing the toggle example, since we recommend starting from an easier example.
Please, let us know.