Install Kali Linux on Virtual box
The easiest way to install Kali Linux on your laptop/desktop is installing it in virtual box.
Here’s a tutorial on how to do it.
Dual booting it on your Laptop/Desktop
It’s a bit advanced and if you are not careful, it also might crash your laptop/desktop, so continue at your own risk
Here’s a tutorial on how to dual boot Kali Linux on a MacBook / iMac
Here’s a tutorial on how to dual boot Kali Linux on a regular laptop / desktop
If you have any questions, you can ask me in the comments section below.