Download the App, search for "Milestone Mobile"
The icon will look something like this:
Once it's done, open the app, select the Plus icon near the bottom and click add server manually.
On that screen, under server details add the name as 428 Internal but you will also have an Address box. Enter 172.16.25.116 in that box. Then add your credentials as shown:
Once done, click the floppy disk icon at the top and milestone should be all set up!
Please note that this app only works on the district's network.