My laptop is lost, how to find it?

If it was activated with a Microsoft account, see below.  Unless it was, or has some other paid tracking service active, the only thing you can do is report the loss to Dell.

https://support.microsoft.com/en-us/account-billing/find-and-lock-a-lost-windows-device-890bf25e-b8ba-d3fe-8253-e98a12f26316

Reporting to Dell:

https://www.dell.com/support/kbdoc/en-us/000129627/how-to-report-a-dell-system-lost-or-stolen