The next thing you’ll need to do is set your working time. This will help Project calculate how long tasks will take to complete. To open this dialog, click the Tools menu and click Change Working Time.

Now, you’ll see a calendar.

The legend on the left tells you how different days appear. You can click any day and change it to a nonworking time (such as a day off), or a nondefault working time.

Let’s say that you’re taking January 2 and 3 off. We’ll click those days to select them, and then click Nonworking time.

You can see that those days now have a line under them. Let’s say too that you are only working half-days on Friday. We’ll click the letter F to select that whole column, click Nondefault working time, and then enter the hours in the boxes on the right.

If we click off of the selection, we can see at a glance when we’re working, when we’re not, and what days are different.

Once you’ve made your changes, click OK to apply them. Like the Project Information dialog, you can re-open this dialog at any time and make additional changes.