Ok i just installed a few Linux and i didn't see a difference exept in the logo debian/red hat.
My first question is how and where is the console that everybody is talking about?

My second question is: I just downloaded firefox and extracted it. Now i want to put it in /opt but it doesn't let me. When i go to permissions he says i am not the owner. What should i do? I want firefox to be recognized in the system.

Which distro are you running now?

I am on Debian now.

if you want to install softwares you need to be root. A general user has no right to write into /opt.
when you boot a linux you need to define runlevel. this runlevel will define how will boot the system, so you will get graphical environment or console.
During the boot phase you can press Ctrl^D to break the boot itself and get the console (as root).
Also you can press Shift-Alt-F1, F2, F3 .... F8 to switch between different displays, you may have console on F1 and GUI on F8.

it seems it more complicated then i thought. is root = administrator?
i found the terminal! is that somehow the console?

I suppose you are new to Linux... If that is the case than you should try Ubuntu, or Mint, or Mageia... Not Debian, nor Red Hat... You can find console in applications start menu under system or accessories depending which desktop environment you are using.
Most of distributions come with Firefox installed by default. In Debian it is not called Firefox, but Ice weasel (ice weasel is unbranded firefox). If you want to copy/move things around your system folder you should get familiar with the console/terminal because, in order to move/copy to and from important folders you need to be super user (root)

thank you. just one more question before i switch to ubuntu. What do you think about Fedora and Gentoo?

Gentoo is definitely the one of the hardest distributions out there (for newbies)... It is extremely fast, but main reason for that is because you install everything... When I say everything I do mean EVERYTHING... From kernel, and xorg server, to drivers needed by your hardware. And installation is pain in the but due to compiling! Yes, everything you want on your system, you need to compile first, and that is slow process. Complete installation of Gentoo lasts from 5-10 hours maybe even more, depending on your hardware! So, my advice is to forget Gentoo even exists (for now)

Fedora is testing distribution for Red Hat, which means, software included in Fedora ends up in Red Hat after thorough testing so all bugs are avoided. Because it is (sort of) testing distribution you will regularly get a problem(s). But Fedora runs latest and the greatest software.

My suggestion would be to use Ubuntu or Mint, and after few months install one of the harder distributions in Virtual Box, get familiar with it and then install it on the hard drive!

Good luck!

Yes, admin is root on unix/linux.
terminal and console are more or less similar, but the real console is a bit different. I assumed you were looking for terminal...
Debian is not really suitable for beginners, but the answers for your questions are almost the same for any linux distributions.

A large part of whether you see a difference, or not, is what GUI you select. Debian with KDE will look quite like Red Hat with KDE. There have been dramatic changes in versions of Gnome recently, so it is quite possible that Gnome might look quite different depending on how recent the distro is and therefore how recent the Gnome is. Gnome and KDE are probably the biggies (in market share and in need for resources) and other GUIs that you might want to look at are XFCE and LXDE, particularly on a lower resource computer.

Neither would be obvious choices in your situation: Fedora is the development area Red Hat, and for that reason is rather bleeding edge. That leads to it having the latest, shiniest, versions of software and that occasionally can lead to a few more bugs than you would like. It would be easier to recommend this to someone with a little more experience.

gentoo is more aimed at a deliberately techie user, and there is a lot of compiling involved. They do try to make that as easy as possible for you, but you'd still be on more solid ground if you were coming to it with a bit of experience.

Ubuntu is a common first choice; there are many things that I'd prefer (including kubuntu/xubuntu, but then I don't really like Gnome, and Mint or Simply Mepis). Obviously, it is much harder to say what you'd prefer, so try some live CDs.

For installing software, most distros that are suitable for beginners will have some kind of software installer or software centre. Tell it what you want, and it will sort it out for you (given network access), but you will need the root password (it will ask). If there is software that you want but can't easily find, there are probably extra software repositories that you have to add, and there will probably be a page in your chosen distro's web site that details what these are, and which it would be advisable to add.

Debian actually is not too difficult for beginners, if one can use the system as is. Everything is in place that most people need. Beginners will probably only have difficulty if they need to configure the system to do something differently. In that case, there is plenty of information in the documentation section of Debian's web-site and on the forum. It would require a little reading and willingness to learn, and a bit of time, but is not impossible.

Why do you want to install Firefox? As Z0K4 mentioned, Debian already has it under the name Iceweasle. Whether you choose Mint, Debian, OpenSuse, etc, you need to familiarise yourself with whichever system you install. Look through the menu to see what you have, open applications to see what they do, read the documentation on that distribution's web-site.