Each subject professors studying one day a week from 8 to 10

[abchaima]

How to Make each subject professors are studying one day in week from 08 to 10

[Volker Dirr]

timeconstraints -> activities -> a set of subactivities has a set of preferd startingtimes

component 1 (so it mean each first subactivity)
maybe use the filter you don't want to do this with all activities.
allow only 08 to 10.