Delete key or me?

[ricuoS <Soucirdeletethisbit@hotmail.com>]

I recently was given an Apple IIe with 2 Disk IIs attached, and a color
monitor.  I sucessfully booted from the "Apple II System Disk 3.2" I
downloaded from the Apple site (I made a 5.25" floppy with an Apple IIe
card in my LC 575), and exited to BASIC.  But when I am typing in BASIC,
whenever I hit the "Delete" key, it outputs a solid square (much like
the blinking cursor square) on the screen.  I can only get rid of these
characters (and other typing mistakes, for that matter) by using the
left arrow key and typing over them.

Am I doing something wrong?  I only recently returned to the Apple II
world.

Thanks for your help,
Joan