Disclaimer: I am not a lawyer and this is not legal advice. The interpretation of the regulations I am giving is based entirely on the reasoning I have seen other hams make in discussing how to operate properly.
There is no one set of rules for the particular band. Rather, there are two entirely separate general regimes:
Title 47 Part 15, for unlicensed operations — which is what the page is telling you is not applicable here. I don't know what the specific reason is, but the usual one is that the transmission is too powerful.
Title 47 Part 97, which defines the amateur radio service and what may be done under an amateur radio license.
For amateur radio operators, most bands are broadly similar; there are no unusual rules that apply specifically to the 5 cm band. There are specific rules,
(1) Amateur stations transmitting in the 5.650-5.725 GHz segment must not cause harmful interference to, and must accept interference from, stations authorized by other nations in the mobile except aeronautical mobile service.
(2) Amateur stations transmitting in the 5.850-5.925 GHz segment must not cause harmful interference to, and must accept interference from, stations authorized by the FCC and other nations in the fixed-satellite (Earth-to-space) and mobile services and also stations authorized by other nations in the fixed service. In the United States, the use of mobile service is restricted to Dedicated Short Range Communications operating in the Intelligent Transportation System.
but these are similar to rules in other bands except for the details of what you're supposed to avoid interfering with. In practice, you are unlikely to need to do anything in particular to comply.
Practically: I assume you don't currently have an amateur radio license. Study for and obtain one, and you'll learn what you need to be doing in general sufficiently to use the particular band you have in mind.
