docs: update hints

Author: BadIdeaException

exercises/concept/appointment-time/.docs/hints.md

@@ -4,7 +4,8 @@
 
 - You need to create a new date. The introduction elaborates on the different ways.
 - `Date.now()` gives you current time in milliseconds
-- A day consist of 24 hour. An hour consist of 60 minutes. A minute consist of 60 seconds. A second consist of 1000 milliseconds. In order to get timestamp of `n` days later from current date, you can sum current timestamp and `n * 24 * 60 * 60 * 1000`.
+- `Date` has several getter methods to get date components - months, hours, etc. - for a given date. `getMinutes`, for instance, returns the minutes component. 
+- Likewise, `Date` has several setter methods to set those components, rolling over into "higher" components if needed. `setMinutes(80)`, for example, will increase the hours component by one and set the minutes component to 20.
 
 ## 2. Convert a date into a timestamp