Rules 4 and 9 of Order XXII of CPC provide for Procedure in case of death of one of several defendants or of sole defendant:--
(1) Where one of two or more defendants dies and the right to sue does not survive against the surviving defendant or defendants alone, or a sole defendant or sole surviving defendant dies and the right to sue survives, the Court, on an application made in that behalf, shall cause the legal representative of the deceased defendant to be made a party and shall proceed with the suit.
(2) Any person so made a party may make any defence appropriate to his character as legal representative of the deceased defendant.
(3) Where within the time limited by law no application is made under Sub-rule (1), the suit shall abate as against the deceased-defendant.
(4) The Court whenever it thinks fit, may exempt the plaintiff from the necessity of substituting the legal representatives of any such defendant who has failed to file a written statement or who, having filed it, has failed to appear and contest the suit at the hearing; and judgment may, in such case, be pronounced against the said defendant notwithstanding the death of such defendant and shall have the same force and effect as if it has been pronounced before death took place.
To answer (1) You need to make an application under Rule 4(1) Order XXII of CPC which shall cause to allow the legal representative of the deceased defendant to be made a party and shall proceed with the suit.
To answer (2) Where within the time limited by law no application is made under Sub-rule (1) of Rule 4, the suit shall abate as against the deceased-defendant.
To answer (3) The application shall contain all the necessary details regarding the death of the defendant or as provided by the court.
To answer (4), All the necessary steps can be taken including depositing the principle amount and filing affidavits by the legal representatives.
Hope i was able to solve your query!