Switch between Piaware and Raspberry Pi OS

Can someone please tell me how to switch between Piaware and Raspberry Pi OS (Firefox already installed) on my Rpi 4b?
Many thanks

Not sure what you mean by switch between the two. Piaware runs in the background and sends data to FlightAware after you start the RPi. If you mean, how do you for example see the status of Piaware – you need to use the command line in the Terminal application on RPi. Hope this helps.

Sorry Jim, got the terminaology wrong. I meant between Piaware and Raspberry Pi OS. I have installed Firefox ESP but don’t know how to access it.

I suppose you are referring to Firefox ESR instead of ESP.
Firefox ESR is an application that can be run om the Raspberry Pi OS and accessed if you are using a GUI (Graphical User Interface) login method.
An example can be found here

Piaware is a process that can be added to the Raspberry PI OS environment as a package install.

If you are using the Piaware image ( based on the Raspberry PI OS) then you don’t have a GUI by default so then only a commandline interface is available.