To duplicate an experiment, you can do it in two ways:
by duplicate the experiment via experiment list
by duplicate the experiment via the experiment designer
Duplicate via Experiment list
If you are on the experiments overview page, you will find a button with 3 dots next to each experiment. In its dropdown you will find the option Duplicate Experiment.
Duplicate via Experiement List
Duplicate via Experiment Designer
If you are on the experiment designer page, you will find a button to duplicate the experiment.
Duplicate via Designer
Duplicated Experiment
If you have duplicated an experiment, you will be required to edit the experiment by name, description, team and environment.
Duplicate Popup
Once you have confirmed that pop-up window, the experiment will be saved and opened in the Experience Designer.