You will notice that the program has recognised your Operating System version.
The purpose of this step is to tell ADLite where your active Basestation database is installed.
Assuming you let Basestation be installed in the default location (ie you did not intentionally change this) AND you had User Account Control turned ON (Windows default) when Basestation was installed then just click [OK].
If you did NOT conform to the above Basestation process, you should click the radio button labelled [I have specified my own location] before clicking [OK]. You will then be presented with the standard Windows folder locator dialogue where you can navigate to the known location of your Basestation database (basestation.sqb).