Question: how to do tawbah prayer?
Answer: Perform Ghusl by way of Irtimasi (submerging the whole body in water, either in stages or at once) or by way of Tartibi (wiping the body with water).
Perform wudu.
Perform a four rakah prayer. ... 
After the prayer, say Astaghfirullah rabbi wa atubu 'ilayh.