When researching tribal law, it is helpful to:
Note that tribes are extra-constitutional, and that the Freedom of Information Act does not apply in gaining access to tribal law.
Use of various terms when searching tribal law including for a specific tribe depends on:
Indexes are crucial in tribal research, when you don't have much familiarity in your subject matter.
Side note: various resources use the term Indian, Native American, Indigenous, American Indian. There is no agreed terminology.