Best way to represent part-time employees

Dear practitioners,
quick question on how to best represent part-time employees in ERPNEXT:

  • Employees with a fixed day off: Granting 52 more days of vacations?
  • Employees working 4 instead fo 8 hrs each day: no idea

I saw the “HR Addon”, but was unable to isntall this to my cloud-based installation hosted by Frappe. ist that by design, or me pressing the wrong buttons?

Best regards,