Not too sure if any of you here have a better step by step guide to either input other website or using the documentation's website.
Either way, I tried both and there was no data index within my Splunk.
In line with the other respondents to this question. The Splunk App for Web Analytics does not handle the actual data input configuration so there is no documentation in the app on how to do this. . For web server data you will most likely use a file monitoring input to monitor the log files generated by the web server. Once that is setup you can start using the app. Please follow the numerous guides and docs out there on how to get data into Splunk.
If needed, the app does contain some sample data you can look at. There are steps in the installation documentation on how to enable the sample data input.