I see a lot of folk suggest http://www.easeus.com/backup-software/
I use other apps but here's a thing. It's not easy. It's easier than it was 20 years ago but you must apply yourself.
-> But if you want to try Ubuntu, why install it? It runs off a memory stick so no install is required.
I have a laptop running win 10, I would like to try Ubuntu OS, to save messing up I would like to backup everything to say a WD external HD, remove everything from the laptop & install Ubuntu OS, if its not a success re-install the Win 10, I would be grateful to know if I can do this easily and safely, with thanks for any help and advice.