The parts of the legislation that set out the details are sections 7 and 8 of the 2017 Act and regulation 4 of the 2020 Regulations.
Y rhannau o’r ddeddfwriaeth sy’n nodi’r manylion yw adrannau 7 ac 8 o Ddeddf 2017 a rheoliadau 4 a 13 o Reoliadau 2020.