from "I have an Icom radio" to "I'm linked to a reflector and talking to a station in Australia" in five steps.
D-STAR runs on a range of amateur radio bands (2 m, 70 cm, 23 cm, 33 cm / 900 MHz, and others). Any of them require an amateur radio license to transmit. A U.S. Technician class license covers the 2 m, 70 cm, and 23 cm repeaters listed on this site. If you're new, the ARRL's getting-licensed page is the place to start.
D-STAR is essentially an Icom mode. Common Utah radios:
To use a gateway (route a call off the local repeater onto the worldwide network or a reflector), your callsign needs to be registered on the D-STAR trust network. One-time, free, two-step process.
Go to regist.dstargateway.org and click Register. Enter your callsign in UPPER CASE, your email address, and a password. A local gateway admin will review and approve (usually within a day or two). Several Utah repeaters run their own registration portal: KF6RAL, NU7TS, K7BSK. You can register on any of them and your callsign will propagate to the rest of the trust network.
Log back in, go to the Personal Information tab, add a terminal:
" ").w7xyz-ht or w7xyz-mobile.Your callsign is now live on the trust network.
Minimum to talk on a D-STAR repeater:
MYCALL = your registered callsign (UPPER CASE)
URCALL = CQCQCQ # local calls, or a routing command
RPT1 = KF6RAL C # local repeater + module, padded to 8 chars
RPT2 = KF6RAL G # gateway (G in col 8), blank for local-only
Easier: use a programming utility like RT Systems or the free CHIRP and import a Utah repeater list. Newer Icoms (ID-52A, IC-9700) have a "Near Repeater" function that pulls in nearby gateways automatically.
CQCQCQ. Keep transmissions short. AMBE doesn't reward long-winded check-ins.REF030CL (link to REF030 module C),
give a short identification, set URCALL back to CQCQCQ, and then call. U
(seven spaces, then U) to unlink the repeater.