How can I specify teachers’ home classrooms?

You can edit any teacher and specify his/her classrooms:

Then in the lesson definition you can specify that the lesson has to be in the one of the teacher's classrooms.

This option is automatically selected for new lessons that have teacher with own classrooms. You can of course allow another classrooms.

Note: if the subject has own classrooms then these are taken as priority and teacher's classrooms are not taken into account by default. So for example if teacher is teaching History in his room and he also teaches Physical Education then PE lessons will by default be only in Gym rooms defined by the subject. Again this can be changed by you at anytime.