I ] Steps for Exporting the data:
1. Login to Salesforce instance.
a) Go to Data Management in Administration Setup section.
b) Click on Data Loader
c) Click the link to download Apex Data Loader.
2. After successful download, a folder will be seen with name Apex Data Loader.
a) Inside the folder, an ApexDataLoader.exe file will be present. Double click on it.
b) A window will open as shown below.
3. To export data from one Salesforce instance to another, Click on Export button.
4. It will take you to login page, enter Salesforce credentials of instance from where user wants to migrate data from.
5. After successful login. Click on Next.
6. Select your Salesforce object and your target file. Click on Next.
7. Edit the SOQL query for extraction. Click on Finish.
II ] Steps for Inserting the data:
Open the CSV file saved during data export. Replace the ENZ_Account__C Id with the new account id of another Salesforce instance where you want to migrate the data to. So all your records or data of Account object from 1st instance will be inserted into this newly replaced ID, as shown below.
1. After exporting the data on CSV file and replacing with ID.
a) Again double click on ApexDataLoader.exe file.
b) A window will open as shown below. Click on Insert for inserting the data on another Salesforce instance.
2. It will take you to login page, enter the Salesforce credentials of instance to which user wants to migrate data or insert the data.
3. After successful login. Click on Next.
4. Select your Salesforce object and your saved CSV file. Click on next.
5. Data Selection pop up window will be opened, click on OK.
6. Map your fields (CSV columns) to the Salesforce object. Click on Next.
7. Select the directory or path where your success and error files will be saved. Click on Finish.
After successful Export and Insert process, Login to the Salesforce instance where you have inserted the data and go to the object to see your attachments.