Have just downloaded and extracted firefox-33.0.3.tar.bz2 file to my Downloads folder. Now a folder called firefox has appeared. Could anyone tell me how i might install Firefox from there please.

you just run firefox from that folder. no installation required.

Big thanks dolphin_oracle for taking the time out to reply.

no problem. to be truly standard, you should copy the folder to /opt. That's where outside installed packages are supposed to go, but it really doesn't matter to much. If you leave firefox in your home folder, it will only be available to your one user. You can always make a .desktop file for firefox and put the .desktop file in /usr/share/applications. then update the menu and firefox should be in your menu.