Availability vs. Time Off
Time Off: Use this to ask your Manager if there are days you need off.
Availability: Use this to communicate to your Manager which time of day, or which days of the week you typically can't work because of school, another job, or an extracurricular activity.
Repeating vs. Weekly Availability
By default, Employees are only able to submit Repeating Availability. This means a date isn't associated with a day of the week. The Employee is simply saying that on Mondays they can't work due to classes all day, for example.
Example of Repeating Availability:
If you want Employees to be able to submit Availability for a date range, Admins will want to enable Weekly Availability (Hover over your profile picture > Company Settings > Availability). The Employee can then specifiy which days they can't work for a specific week.
Example of Weekly Availability:
Whether you want to use Repeating Availability only, or Repeating and Weekly, you will likely want to enable Availability Reasons.