How to make your any Important surfing tabs as a default tab in very small size along with home page

First surf your firefox and open your inportant link. like gmail or facebook ,etc.
then visit the tab which you want to make default tab in small size.
Now right click on the particular tab and choose " Pin as app tab ".
now you will see that near the "Firefox button" a small tab. that will be your choosed tab.
this can be done with a no. of tabs.