Hi Pittayaporn, 

Welcome to Box Community and glad to assist!

Are you experiencing a particular error while uploading files? Also, are you uploading your files using your local Box folder or with box.com? 

Looks like you're uploading on a  shared folder since you don't have your own folder. At this rate, you may verify if you have permission to upload files. 

We have also listed down the troubleshooting steps to fix your upload issue. 

Hope it helps!