a regular gst dealer should maintain some bokks.

Dear Suraj,
What is the nature of your business,
and it is better if you can maintain books of account like soft copy in computer,
cash , Bank book will help your reconcile with your debtors or creditors books.

Sales register with GST. no, state code, POS,HSN ,party name,bill no and date.

purchase register
stock register. etc

this books also help when you claim GST input which you will file in GSTR2.