Hi usc1000, welcome to the board.
There are several ways to do this.
One way, use a helper column to identify the duplicates using a formula like this -
copied all the way down.
This will put a 1 next to any item that appears more than once, and a 0 next to any item that appears only once.
Then use data, filter, to display only the rows with a 1 in the helper column, and delete them.