Yes the language inside [code] tags are commands and they are meant to be pasted in Applications > Accessories > Terminal.
But don't blindly follow any command from any website other than ubuntuforums as you don't know what that command is going to do.
Neither blindly follow any command from the forums also unless you exactly you've got the same issue. If you are not sure, feel free to post a new Thread and let the mates answer you specifically.
For copying the commands, you can highlight a line in your browser, open up Terminal and just hit middle-click button on your mouse. Or you can simply copy/paste.
The commands that look like this.
They need to be copied one by one and after the prior one has completed its operation and you are returned to your user@computer: prompt in Terminal.
And when running a command as super-user with a sudo in front e.g,
It would ask for your password in the Terminal and when you type it, you wont see any characters or asterisks. You just need to type blindly and hit <Enter>.