If you see Delete multiple persons in FTM with same name. if you have not created them but it was a system generated. therefore you need to delete multiple person. Use any chart in publish workspace in family tree maker.

It is always better for you to keep only those people in the chart from your own family. You can work on the chart and narrow down the list. If the chart has list of those people which must be remove, you need to click anywhere over the chart and select