By default Firefox will not open your predefined HomePage with new open TAB. To change this default behaviour you need to open your about:config page and change some values. Enter about:config into your navigation bar. This will open up hidden firefox settings page. Into the search enter:
This will display single variable responsible for new tab. Double click on a value column and enter your desired homepage. Example: https://jobs.linuxcareers.com/ Now, every time you open a new TAB your TAB will open your homepage.