Refuting an argument chapter 7

According to Epstein, there are two ways to refute an argument: directly and indirectly (149).

Direct ways of refuting an argument

• Show that at least one of the premises is dubious.
• Show that the argument isn't valid or strong.
• Show that the conclusion is false.

This will help me to understand what premises are false or dubious or if the conclusion don't make any sense.
here's an argument:

Alex: I believe that homework should be done in class.
It saves time.
Students barely have any time outside of class to do homework.
Some people have work, while others have other activities.
Besides the teacher is not there in case we need help.

Now here's Dane refute to his argument:

Class time is meant for lectures and new lessons.
There are tutors on campus in case a student needs help with homework.
Some people who have jobs do have time to do homework. ( their work schedule is planed around their classes and leave enough time for HW).

The indirect way to refute an argument is to simply not mention them, but to know that they are false or dubious, for example listening to a speech on TV.