Runn assumes the working week for everyone is Monday → Friday, but we know things in the real world are never quite that simple...
If someone works "Monday - Thursday"
Create a time off entry to block out the days that person isn't working. For example, if someone does not work Fridays, make their Fridays unavailable by adding "Time Off" to their schedule.
Note: You'll need to manually this add "time off" to every Friday, currently you can't say "Make all Friday's non working days".
If someone regularly works weekends
Runn doesn't deal with this yet... but it's on our roadmap. If this is a problem for you, let us know and we'll bump it up the priority list :-)