SOLUTION FOR DATA MIGRATION

1. First Identify the following record ID which will be used to update records in the following objects;
   1. Account ID Field in General Estate Opportunity Records
   2. Opportunity Number Field in General Estate Payment Instalment. 
2. To Get the Id Select the record for eg Sule Adamu Account and copy the following URL id: https://YourInstanceName/lightning/r/Account/0018d00000XYf0dXXX  (copy the bolded text only and add to General Estate Opportunity Record CSV column “Account Name”)
3. Same thing for Opportunity Field for General Estate Payment Instalment, https://YourInstanceName/lightning/r/Opportunity/0068d00000FH6DcXXM (copy the bolded text only and add to General Estate Payment Instalment Record CSV column “Opportunity Name”)
4. Save both CSV File and they are ready for upload
5. Navigate to Setup -> Integrations ->Data import Wizard
6. Upload the Files in the following order; 
   1. General Estate Customer Records to Account Object
   2. General Estate Opportunity Records to Opportunity Object
   3. General Estate Payment Instalment to Payment Instalment Object.