How can I swap all the lessons from one period to another

Once you generate your timetable and wish to just swap lessons between periods, it is not necessary to do it manually "one-by-one" card. It is convenient to use advanced function "!swapdpd".

If, e.g. you wish to swap second period in Monday with fifth period in Tuesday you can do so in the menu Options - Advanced and type following in Advanced field:

!swapdpd 1 2 1 2 5

press OK.
This will swap:
from
1 - 1st day in the timetable (so Monday in our case)
2 - 2nd period
1 - copy 1 period (2 would copy 2 periods, and so on)
to
2 - 2nd day the timetable (Tuesday)
5 - 5th period

Note:
In case, that there are longer lessons (double, tripple, ...) in area you wish to swap, this function will move just those long lessons, which starts on specified periods.