My tree has 5 or 6 duplicates

Welcome to the club. Family Tree was created from several different previous databases such as the International Genealogy Index, the Ancestral File, and the Vital Records Index. Since each individual doing genealogy would submit their work independently, these databases were full of duplicates. The immediate predecessor of Family Tree which was called New Family Search, had several hundred duplicates of my great-great-grandfather. Over the past years, these have all be combined into one, single profile in Family Tree.

Our work as users here in Family Tree is to get our families all properly combined with one and only one copy of each person and with all the data corrected and documented through proper sources.

So pick a place to start with your family and go one person at a time to combine duplicates, correct personal data, and correctly untangle relationships. If this looks overwhelming, again just look at one person at a time, view it as a couple of years worth of worthwhile work, and go drop into your local FamilySearch Center for advice and help. You can locate nearby FamilySearch Centers by clicking on the map location pin on the righthand side of the very top menu bar:

Do keep in mind as you work that Family Tree is one universal wiki-style tree that we are all working in together. That means that in the "mixed up relations" you are seeing, there may be people that belong to different family lines than yours. You will on occasion find that someone else thinks your g-g-g-grandfather is his g-g-g-grandfather when they are really two different people. So sometimes when correcting your relatives you will need to also correct someone else's relatives as well.

Good luck and have fun on this project you have ahead of you!

Wonderful! So many data problems have been "surfaced" for someone to fix in one fell swoop. On Family Tree they can be fixed, and you can be that someone who does the fixing. Think how many cousins, near and far, you will please.