Step 1: set a cessation date and freeze new activity
Pick the date trading stops and tell staff, customers and suppliers. From that date, the books record only wind-down transactions: collecting what is owed, paying what is due, selling assets and settling with employees. Any new sale after the cessation date complicates the tax position and the liquidation.
Close the books at the cessation date as you would a year end: reconcile every bank account, count any stock, and list every open invoice and bill.