After finishing the download process, you find the icon with the name aladinSetup0.exe on your desktop. Double click on that icon and the installation of the program kesa-aladin will be started.
Note: The kesa-aladin program runs as a demo unless you buy a licence. You can work with the demo as if you worked with the full version. However, the number of calculations you can do with the demo version is limited.
The aladinSetup0.exe icon looks like this.