(StepD). The antigenome (+) undergoes self-ligation to form the circular template for the genomic RNA (-) (Step E). The virus uses RNA polymerase II again to transcribe copies of the genome.
Assembly of the HDV virion requires the envelope proteins (HBsAg) of the helper hepadnavirus, HBV. Without the envelope the virus cannot replicate properly. This is why coinfection or super infection with HBV is necessary.