go here
http://www.cmsmadesimple.org/downloads
clik .tar or .zip to download latest stable release,
untar/unzip, open FTP connection to your server, on the local side of FTP find cmsmadesimple folder, open it so you see admin and etc. folders
on the server/site side, depending on how your set up, clik to open that side to show the same admin and etc. folders,
hilite admin and etc. on local side, upload to server/site it will have folder 'install' now, Navigate to or site /install/upgrade.php. That automatically makes any necessary changes in the database.
you could read this
http://wiki.cmsmadesimple.org/index.php ... /Upgrading
the last line is from there.
you will want to go back and delete the 'install' folder, it warns you when you log on after upgrade.
HTH
mark