You need to run the command prompt until it appears. The command prompt is the big black or blue box where arcane text appears, and into which you can type things. Try running it from Windows Accessories in the Start Menu, which is where I think it's found.
Click into the command prompt to enter text. Type a command an press enter to do that command. Folder is another word for directory.
dir lets you view the contents of a directory. You can type it alone to view the contents of the current directory, or type the name of a directory to view that directory. It helps to press the tab key after typing the first few letters of a directory, as this autocompletes. Might be a couple second delay.
cd lets you change a directory. Type cd and then the name of a directory to switch to that directory. Type cd .. to move up or back one directory.
You can also autocorrect the names of programs you have in a directory, again by using the tab key.
cd and dir are completely harmless, spend a few minutes cd-ing around and dir-ing things to get the hang of it, and to understand how to get from where the command prompt starts to where your personal files are located.
Type the name of a command followed by --help (which is called a parameter) to get more info on using that command.