Hi servalstudios. To assign the classes to your employees, you will need to edit your payroll settings. It's actually quick and easy and I can guide you through in just a few steps. Here's how:

1. Select the Gear Icon in the top right corner
2. After that, select Payroll Settings under the Your Company tab

3. Choose Accounting.

4. In the Classes section, select I use different classes for different employees.
5. Click on OK.
6. In the Preferences - Employee Classes section, assign a class for each employee. 
7. Click on OK.

You'll be prompted as well as to select a date for the changes to take effect from. Just select the desired date and everything will automatically be reclassified. Let me know if this helps, and feel free to leave a reply if you need anything else.Have a great rest of your day