When working in Week view you can add an item by clicking on the Create button at the top left. It will default to the first day of the given week. You'll be able to change the date when creating the item.
You can schedule as far in advance as you wish. You can move to the next week or skip back to prior weeks by using the arrows at the top right.
You can click on the blue linked text indicating a specific day to switch to a Day view.