In college assignment research, we often start with basic print-format markers to help us decide if a source is from a "good authority" for our topic -- things like the type of publication (example: academic journals, scholarly books) or author credentials (an author's listed titles or affiliations).
When considering sources across cultures, you will want to be open to different formats -- think about how authority is constructed in different cultures, and that influence and authority may look different in different communities. Some sources may not have "traditional" print text, but a known authority on your topic is providing good information in a different format - an oral history, an interview, a lecture or speech, etc.
Example: 2018-2019 GRC One Book title, March, Book 3, is an example of a history of the African American Civil Rights Movement told as an authoritative, first-hand account in a comic book format:
Many of the sources you'll use in the library and online will assume an American or English-speaking audience by default, and so when you read / use these sources, make sure to note who the author is addressing and what the boundaries, or scope, of the source seem to be.
You don't have to cover every possible cultural perspective, but there are times when it might be useful to be able to draw your audience's attention to the fact that a quote or source is speaking only or largely about one cultural viewpoint.
You can balance out sources that seem to be focusing too heavily on one particular cultural narrative by locating other sources that - while having good authority - show other perspectives:
Research is a process.
Step 1: Understand your assignment
Step 2: Start with a general topic idea
Step 3: Find information
Step 4: Evaluate
Step 5: Cite Your Sources