Update a Google Sheet for any transaction

Hello,

I have to update a Google Sheet for any transaction of customers.

First Scenario:

A New Customer “A01” has made a new transaction today, So need to do below steps:

  1. Open the Google Sheet
  2. Add the Customer Number “A01”.
  3. Add Transaction Date(Todays Date), Exactly below the customer number.

Another New Customer “B01” has made a transaction today, So again repeat step 1-3 for “B01” Customer.

Second Scenario

After Somedays, An Old Customer “A01” has made another new transaction, So need to do below steps:

  1. Open the Google Sheet
  2. Search for the old Customer Number “A01”.
  3. Add Transaction Date(Todays Date), Exactly below the last date of transaction.

So here it will keep updating transaction dates for old customer and keep adding any new customer as shown below:

Any Solution for this.