I compiled the 2.1.6 firmware demo last night and conneccted to it via http://IP_Address:8080. I also compiled the 2.1.7 firmware demo last night to play around with it. I had to connect to it using http://IP_Address even through the advanced options shows 8080 as the listen port.
The interface is pretty much self explanatory but https://opensprinkler.freshdesk.com/support/home has all the information you need to test it.