Only insert or remove the flash drive with RPi OS when RPi is turned off (i.e., when it is not powered).
Install the required software on your computer, see Software.
With RPi turned off (i.e., not powered), plug in the drive with the OS. Connect the RPi to your laptop via Ethernet cable.
Now turn on the RPi by connecting the power. Wait a few minutes to make sure the RPi has booted.
Use SSH on your laptop to access the RPi (see Connecting with SSH). The IP address is "raspberrypi.local” (without the quotes). If you encounter any issues, try again (the RPi may not have booted yet completely).
In the SSH window, find the IP address of your Ethernet connection, as explained in Find the IP address.
Now open the VNC Viewer on your laptop (see Connecting with VNC). Use the IP address from the previous step. This will give you access to the RPi desktop.