I dont know if i understand right, but i think you want that FIrefox Start with the default page and other tabs.

To do this go to Tools >> Options >> General >> in the Home Page form, write the links of the pages that you want and between they write a |, for example:

google.com | uol.com | yahoo.com

• How to set the home page

Thank you very much, but if I put other addresses into the bar I no longer have Firefox start page.

Put about:home|google.com

about:home is the "link" to default firefox home page

You can open only the pages that you want as the home pages in tabs and click "Use Current Pages" to set all these tabs a multiple home pages.

• Tools > Options > General > Startup: Home page

Firefox supports multiple home pages separated by '|' (pipe) symbols.

• https://support.mozilla.org/kb/How+to+set+the+home+page

You would have to open other pages/links in a new tab if you want to keep these pages open in the first tab.
Otherwise those pages get replaced by the page that you open and you would have to close those tabs and once again click the toolbar Home button.