How to turn on a Dell laptop depends on your laptop model and operating system. Here are a few common methods:

1. Press the power button: Find your computer's power button, usually on the top or side of the keyboard, and press and hold it for a few seconds until the computer starts.

2. Power management key: Some Dell notebooks have dedicated power management keys, which can be found on the side or bottom. Press this key to start the notebook.

3. Plug in the power adapter: If your laptop has a battery, you can try plugging in the power adapter and taking it out to fully charge it before unplugging it. Typically the adapter connection is on the left or right side.

4. Wake up from sleep state: If your notebook is in sleep state, press any key or open the lid to wake it up.

5. Shortcut key combinations: Some Dell laptops may have specific shortcut key combinations to boot. This requires checking the user manual for the specific model for the correct combination.

The above is the answer on how to turn on a Dell laptop. Please perform the corresponding operations according to the device you are using.