Please select the wanted partition size for Android and for Linux:

   
android linux
   
Android Linux
   
 
By default boot into Linux

If you select the "By default boot into Linux" option above, then your Gemini will boot into Linux by default, and it will boot into Android if you press the side button when booting. If you left it deselected, then your Gemini will boot into Android by default, and it will boot into Linux if you press the side button when booting.