4. If I'm idle for about 10 minutes, my screen turns black, how do I turn that off or start a screen saver?

To disable blanking for the text consoles: setterm -blank 0

To disable X server screen blanking: xset s off

These lines should precede the one that execs your window manager.
My .xsession is:

(seems like .xinitrc would also work with this)

===========================
#!/bin/sh

setterm -blank 0 -powersave off -powerdown 0
xset s off
xscreensaver &   # or  gnome-screensaver &
exec fvwm2


So how do I disable the blank screen mode, which activated after a few minutes? Answer is use setterm command.

setterm writes to standard output a character string that will invoke the specified terminal capabilities. Where possible terminfo database (terminfo is a data base describing terminals, used by screen-oriented programs and libraries such as ncurses) is consulted to find the string to use.

By default, the Linux kernel will use screen-save option to disable it you need to type command (it turns off monitor VESA powersaving features):

$ setterm -powersave off -blank 0

If it dumps back you with an error that read as follows:
cannot (un)set powersave mode

You need to shutdown X window system and rerun the above command.