You only need to be su for "make install", and it's better not to use the trailing hyphen when doing "su" so you remain in the same directory.

Example:

me@host$ pwd
/usr/src/samba/samba-3.0.1
me@host$ ./configure
...scrolling list of checks...
...scrolling list of checks...
...scrolling list of checks...

me@host$ make
...compiler runs...
...compiler runs...
...compiler runs...

me@host$ su
Password:

root@host# pwd
/usr/src/samba/samba-3.0.1
root@host# make install

You might also want to run updatedb after the install finishes, so you know where everything is located. The Samba configuration file is smb.conf (usually /etc/samba/smb.conf), but usually it gets installed as smb.conf.example or smb.conf.dist (depending on which platform you're on.)

When you use the hyphen with "su" all the environmental variables are loaded and applied to root's environment, like $SHELL, $PATH, $DISPLAY, and so on, and you are transferred to root's $HOME (usually /root )

By not using the trailing hyphen, you remain in the same directory, keep the same $SHELL (if root's $SHELL is different) and get what you want - root access. It's always recommended to install sudo, so you wouldn't have to go through all this to begin with. (me@host$ sudo make install)

Hope this helps to clear things up for you..