Why can't I key in the hours that staff worked?

Let me help, @celiacao.

It's possible that your time tracking was turned off in the company's setting. You'll need to set your time tracking preferences first before you can create a Single Time Activity or Weekly Timesheet.

Here's how to turn on time tracking:

1. Go to Settings ⚙ and select Account and Settings.
2. Select Advanced.
3. In the Time tracking section, select Edit ✏.
4. Set your time tracking preferences.
5. Select Save, then Done.

You can also check this article for more details: How to turn on and set up time tracking.

Your employee can also fill out a Weekly Time Sheet or a Single Activity Time Sheet by adding a time tracking user. 

If you need to update your company settings, you may also check the related discussions below.

How to configure company settings

How do I set my advanced account settings?

That's it. If you have other questions about tracking hours, please know that I'm always around to help.