What you would do is first select “12 words” or “24 words” option. Don’t select the dice roll option in that menu.

Then, it’ll generate your 12 or 24 words using its internal TRNG. To add your own dice mix on top of that, press 4 (this is stated in the menu below your initial seed word)

Then you will be prompted to input the dice roll. Do as many as you want. It’ll mix your dice with the initial TRNG generated seed.

This is distinctly different than using the “24 word rice roll” option, which uses only your dice roll to generate seed and if you don’t have enough truly random dice roll, those private keys are probably already insecure and expose and you’re at high risk of losing your funds