In order to insert a line numbering restart at a specific section of your document, you will need to follow these steps:

1. Go to the specific section in the document
2. Click on the ‘Insert’ tab at the top of the page
3. Choose ‘Page Numbers’ from the dropdown menu
4. Click on the ‘Format Page Numbers’ option from the dropdown menu
5. Select the ‘Restart at each section’ option from the ‘Page Numbering’ tab

Once you have followed those steps, you will have successfully inserted a line numbering restart at the specific section of your document.