In your Transaction sheet, try clicking on the Filter option in the Google Sheets tool bar (the small funnel). Then, in the Category column header, click the Funnel icon (upside down triangle). In the dialogue that appears, select “Clear” then put a check mark next to your Grocery category name. Click “OK,” and your sheet will be filtered to show only the transactions that are groceries. You can filter further, if you wish, in the same way.
To find just Ralph’s, you can filter on the Description column header in the same manner, and find the transactions only for one or more vendors.
Be sure to turn off your filter when your done to return to the full list.
Does that help?