How can I rename days?

The software allows you to define your day names and short names in case you want to change the defaults:

If your school has 2 different days Day A and Day B where DayA is Monday, Wednesday and Friday and Day B is Tuesday and Thursday. Then you can create new days A and B. Just use button combine:

Then you can define dayB as combination of Tuesday and Friday. You will end up with two special days A and B:

For each lesson, you can then define that this lesson can be on day A or B. Simply input the short name in the field with lesson counts. If you specified A, lesson will be placed on MW and F: