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1. Add that in Remote Security setting with name – "Instance"
2. Copy the first part of the URL address to the Remote Site URL. Refer the underlined URL in the picture
3. Click on Save button, it looks as below once saved

Once the Remote site is added in the settings, the page needs to be retrieved to do this follow the below steps

Click on the Admin/Get Started object, scroll down to Retrieve Page Layouts related detail and click on the button Retrieve Page Layouts 

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On Clicking the button Retrieve Page Layouts the following page pops up and takes you back to the same page 

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Enable Left side AccountingBook Links

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