This article explains where to find the power button on a Dell laptop so you can turn it on and off.
Dell Laptop Won't Turn On! Laptop Won't Turn On Dell
This is how almost all Dell laptops turn on (exceptions are noted below):
Connect the power cord to the laptop's charging port and the other end to a wall outlet. You can skip this step if you are sure that the laptop's battery is sufficiently charged.
Find the power button and press it.
