Yes, there is a function to find duplicates. After you find them you can view the information and select what to keep and/or merge. I found it very simple to use.
I personally used the 'download online tree to computer' since I did not want a second tree duplicated online with all the links, etc. I figured I could easily delete the duplicated tree on my computer and it would not cause a problem online.
Good luck wilmeloc65 - enjoy your new home! Lots of work but hopefully worth it!