For Windows ONLY, you will first be prompted to choose between installing for all users or not; choose whichever you prefer (see image at left).
On a Mac, it will install for all users by default; this can be changed later in the installation sequence.
Next, you will see a screen like this when installer starts:
Click through each of the sections (License, Destination Select, Installation Type, Installation, Summary). When given options, if you are uncertain, use the default suggested by the installer. Eventually, you will arrive at this screen:
That's it. Now you can code in Python using Thonny on your laptop!