I spent days looking for a Time Tracker and finally found this gem. Usually, we have high expectations for the popular apps, but look what I've found. I would definitely recommend WebWork to anyone. When my team grows or someday I start my own company, I will definitely support this company.

Locate the .deb file on your computer and run it to install WebWork Time Tracker

Enter your sudo password if necessary,
WebWork will be installed, you can now open and use it