How to duplicate ad sets

Go to 'Launch' and select campaign

Go to 'Adset' and choose the adset you want to duplicate

Change the settings you need

New Name: Change the name of the new ad set
Edit Dates: Gives you the option to change start- & end-date
Edit Budget: Let’s you change the budget (if the budget is set to ABO)
Launch as Active: Gives you the option to publish the new ad set active or inactive

When you are happy with the adjustments, click 'Copy'

You can now see your new ad set, created with the same settings as the previous one.NOTE: We’ve made an exact copy of all settings, including optimization goal, audience, and placement options.
The only difference is what you just changed in the previous window.This ad set is fresh and contains no ads - ready for you to launch new ads into.