I generally take the scheme folder and put it inside the arc folder. This is not required, but earlier I found it easier to manage as they become one movable install.
Arc is best suited to unix/linux or mac operating systems. Arc has some issues on Windows, but In the past I still managed to get it working on windows.
If you're using a unix/linux or mac os you need to find the Terminal application that is already there and launch it.
In the terminal window you need to navigate to the arc directory. You can do this by typing 'cd' (change directory)
followed by the path to the arc folder...
In my case:
Terminal $ cd /users/thaddeus/arc
If all goes well, as a test, you should be able to type 'ls' which will show you the files existing in the arc directory.
Terminal $ ls
now to you can invoke arc by typing (note change the paths to respect your install directories):
Windows is similar only you're using the 'cmd' utility rather than the terminal.
You can start 'cmd' (command prompt) by going to your operating systems 'Start' button then select 'Run' and type 'cmd' into the text entry box (& hit 'ok'). A dialog window should come up. Here you also need to navigate to the arc directory:
Mine starts like this:
C:\Documents and Settings\thaddeus>_
So I change the path to the arc directory like so (note change the paths to respect your install directories):
C:\Documents and Settings\thaddeus> cd C:\thaddeus\arc
I typed all this up on my lunch hour at work, so I didn't actually do the steps - just memory recall. So if you hit a snag ask, I may have typed something wrong.