This article will cover the steps required to get Kali up and running in Oracle VirtualBox so you can try out the operating system and learn about ethical hacking.
VirtualBox
Browse to the VirtualBox downloads page and select the appropriate download for your operating system. Also from this page, download the VirtualBox Extension Pack.

For macOS, click the link for your appropriate host – either Intel or Apple Silicon, this will start the download process. Once the download has completed, follow the installer prompts keeping with the default options.
When VirtualBox has finished installing, open the app and then select Extensions, found half way down on the left-hand side. Click the Install button and browse to the location of the downloaded extension pack, click Open.

Read the extension pack installation confirmation screen and click Install.

Click I agree on the licence screen and enter the password, if prompted, for your macOS user account to allow the installation to continue. Once the installation has completed you will see the extension pack listed.

Kali
Download and install
Browse to the Virtual Machines section of the download page. From the VirtualBox section, select either the direct download or Torrent download. I went with direct download although if you prefer, Torrent is an option.

Extract the downloaded file, this should provide a folder containing a vbox file and a vdi file.

Next, open VirtualBox and select Home -> Preferences -> General. Review the Default Machine Folder, select a new location if required, otherwise, leave the setting as-is and they will be created in a folder under your user profile. Click OK.

At this point, move the extracted folder to the location (Default Machine Folder) specified in the previous step.
From the VirutalBox toolbar, select Open. From the file browser window that opens, select the kali-linux folder and then the vbox file. Click Open.

The VM will then be shown in the VirtualBox Manager app.

You can review the VM configuration and adjust as desired, for example increasing the CPU count and the RAM, by clicking Settings in the toolbar.
Configuration
Power on the VM by selecting it and clicking Start.
After a short moment, the following screen will appear. You can click into the VM and hit return to select the option or just let the five-second timer run down and allow the autoboot of Kali to start.

Once loaded, you will be presented with a login screen. The default credentials are kali/kali. Note: you can change these to secure the login, or leave them as default as it is a VM running on your local machine.

Verify the network connection
With Kali now loaded, look to the top-right corner and select the ethernet port icon (next to the clock). This will show that the ethernet network is connected to Wired connection 1.

The network connection can be tested by opening the web browser (Firefox is available by default) and browsing to a URL.

Congratulations – you now have access to Kali Linux!