In Hightrack, Free users can only have one local calendar, plus another external, read-only calendar (Google Calendar or iCloud).
Premium users have unlimited calendars, both local and external.
On the Sidebar, just click on the [+] icon to add a new calendar. Repeat for as many calendars as you need (for example, your Professional, Personal and Family calendars). Then you will be able to see all the info at once or by Calendar.