All APIs require authorization to clarify what is allowed and what should be seen. The scopes requested at the time of creation can always be less than the total amount available to enable you to use the principle of least privilege.
InfoBe sure to go through the developer onboarding and the authorization section for more details on authentication.
Also, it's worth noting the token created when you logged in and signed up using the top right, those tokens only last for 4 hours (and sometimes go wonky). So you may need to log in and out from time to time.
Use the recipe below for a step-by-step on authentication logic.
Don't bother testing on this page.
The server timestamp deviation cannot be more than 5 seconds from the epoch, which gives almost no time to generate values and paste them in here.