You can only add additional Tabs to a "folder structures" not to a Panel.  Instead, you can make your JT_Employee screen bigger by clicking on Panel, Header, Select Tab 2 (Position & Size), and changing the Size to support your UDF's.  

Is there anyway to add "folder structures" to the JT_Employee screen? I am asking because the UDF's are going to be more than we could probably have on that screen. 

Is there a way to create a custom screen from scratch instead?

if you have more than a dozen or so UDF's for that screen, you may want to talk with your Sage 100 Consultant and involve a master developer to enhance the screen for you.  That Panel in custom office can't include TABS without developer work. 

Awesome, thank you very much!

Have you considered a button pop-up panel instead?  No Master Developer required, and you can have many, making the pop-ups as big as you want.

This will do perfect! 

Thank you!