Dell XPS 15 9570 RAM Upgrade

Buy Crucial RAM. The Corsair Vengeance is high performance RAM, such as for gaming, and may not be compatible with your laptop. Here is a list of what Crucial guarantees to be compatible with your laptop. 

You didn't specify your processor, so I couldn't check its spec. Many 8th-generation CPUs are limited to run RAM at 2666 MHz. So, even if you buy 3200 MHz RAM it may downclock (run more slowly) to 2666 MHz. You can search for your processor at Intel site to see memory specs for it.

Whenever touching components or working inside a computer, wear a grounded wrist strap, also called anti-static wrist strap, ESD wrist strap, or ground bracelet. It's a cheap and sensible precaution. Rest the laptop on an anti-static mat or at least a reasonable alternative such as corrugated cardboard.