Fairly simple to connect with the classic client.
Download the official client.
Download UO Razor
After installing the official client and either installing or extracting Razor, run Razor.exe
It should help you find your UO client.
Add a new server, the server name can be whatever you want, Bujin UO or SALAD! or whatever.
Server Host:
salad.yarrdev.com
Port:
2593
Enhanced Client
While buggier, it has a more modern interface. If you would rather use it I have configured and uploaded a launcher for it.