Either one. You need to use cd if you're specifying a file path "relatively" (like when you type ./filename, that's a relative path to "filename" if you're in the same folder as the file "filename". When a path starts with / it's an absolute path, going all the way from the root folder "/" to where it actually is. You can specify absolute paths from anywhere and they'll be the same, but you have to specify a different relative path for the same file whenever you're in a different directory.)

As for chmod, I explained that command to you a while ago. It's the one that changes the file's permissions. If that doesn't ring a bell, you can read the post I originally posted to help you with one of your first questions.

Also, here's a really good tutorial on the basics of using x-terminal/command-line in Linux. I strongly recommend you read through it over the next few days/weeks, whenever you get the time, because it's explains all of the basics:
http://linuxcommand.org/learning_the_shell.php

Also, the instructions didn't say it will be "mounted", the instructions said "UNmounted". That basically means that it 'shuts down' the chroot. It's just something you do after you finish using it, so that it turns it off/disconnects the chrooted file system, as I understand it. I'm not sure if anything WOULD happen, actually, that you would see.