Dell XPS 15 - factory reset

I recently installed Ubuntu 18.04 alongside Windows 10 in my new Dell XPS 15 7590, but it doesn't work as it's supposed to, so I want to completely factory restore my laptop's SSD, which means I want to delete all windows partitions and make laptop behave as if brand-new. However I haven't found a way how to do it, I've visited many websites with possible solution but I am desperate. I am afraid that I can delete partitions which are necessary for proper functioning of a machine because I can't recognize which ones are necessary for proper functioning.

Thanks for any help.

• Is there a way to completely factory reset the laptop?
• How can i uninstall Linux and set partition settings to default?