This year's graduates don't have many such practices (except some). They usually write about the school, just write about some activities you participated in at school and take some ideas as employee activities! If you have participated in some volunteer activities, you can also write. The key is to let the interviewer know that you have these experiences and let him know your ability!

So you should choose to write, and don't list too many similar things, which will make the interviewer don't want to see it! Continuous time is ok, you don't have to write if you don't have activities in winter and summer vacation!

And your last question, "Just write down when and where to study". You'd better write according to when and where you study!