You need to enable a config to auto refresh the list in your Google Sheet whenever you open it. Select Add-ons → Drive Explorer → Configuration, check "Autorefresh on open" and click on
Save. You may also want to check Scheduled refresh.
If you constantly update the files/folders in the folders you have picked for listing in the sheet, you will find this config much useful. You can also manually update the list by selecting Add-ons → Drive Explorer → Refresh.