That is a choice, GPT is the better option imo, but ms-dos works too.
If choosing GPT, then yes, either do as the doc states, or use manual option in Calamares, and set it the same way as in the doc. Automated in Calamares still falls back to ms-dos if BIOS system is detected, but work is ongoing in Cala to make automated whole disk option always use GPT (so UEFI and BIOS).