Right click the link you want to open a new tab and click on Open in new tab if that is what you are asking for.

You can hit Ctrl + T. This is the easiest way for me

Also see http://support.mozilla.com/en-US/kb/Tabbed+browsing#Open_a_new_blank_tab

what i was referring to would be while on a tab that isnt at the end i think of something i want to look up. i hit cntrl t and instead of the new tab opening next to the current one it opens all the way at the end. i was wondering if there was a way to make it open next to the current one