"maximized" Firefox

Hello to all. People advised trying to ask on this forum. Maybe someone can help me.
This is: https://support.mozilla.org/en-US/questions/1295098#answer-1333341 a link to a question I created where I already asked him, but so far no one has suggested a working method.
Question itself:
"How can I launch Firefox in full screen mode? I created an executable file for simultaneously launching two browser tabs at once. He works. But I need the browser itself to open in full screen mode. In this form, as if the "deploy" button was pressed. Please tell me what you need to add to the lines of the executable file. Or maybe there is another way. Here is the data of the executable file: start "" "D: \\ Browser \ firefox.exe" https://www.google.com/ https://yandex.by/ "