Please can someone explain how I delete a name on my family tree that I added in error
We understand you wish to delete a name on your Family Tree that you added in error. Is this one that you created? If so you may be able to delete it, by going to this individuals Details page, and scroll down right for the Tools section, and press Delete Person, giving a reason, and press Delete again.
If the Delete Person is unavailable, you may need to delete the relationship, by clicking the Edit pencil in the line beside the name, and Remove the individual from the relationship; either as a child of the wrong parents, or as a spouse. The two article links below may be helpful.
For Child: https://www.familysearch.org/en/help/helpcenter/article/how-do-i-correct-parent-child-relationships-in-family-tree
For Spouse: https://www.familysearch.org/en/help/helpcenter/article/a-person-in-family-tree-has-the-wrong-spouse