Access your personal schedule in MyTimetable, the timetable website of Utrecht University. Log on using your Solis-id and password. Your personal schedule is also accessible through the MyUU app.
See our year calendar 2017-2018 (pdf) for an overview of blocks, semesters and registration periods in this academic year.
The Dutch government offers an overview of the 2017-18 school holidays (in Dutch).
Timeslots divide the week in different parts to prevent a clash in course times. It is usually not possible to choose courses that are scheduled in the same timeslot.