How do I use the contents of a variable as the name for another variable?

This very easy to do in Perl but that doesn't mean you should do it; you probably (almost certainly) shouldn't.

You can do it like this.

$v = 'myscalarvar';
$$v = 1; # same as saying $myscalarvar = 1

But don't do it.

What if you have code like this:

$x = 'hello';
$z = 'x';
$$z = 'goodbye';

What's the value of $x at the end of that?

Use a hash instead - like this:

$mylist{arrive} ='hello';
$mylist{leave} ='goodbye';
$mylist{wait} ='slouch';

That will do exactly as you want and won't collide with other variables.