DSL Talk

I just sucessfully completed my first frugal installation and would sure like to know the steps required to upgrade when a new upgrade comes out ? I read something about replacing the single big compressed file called/knoppix, Is that all there is to it ? How do I replace /knoppix ?
I have been downloading the newest .iso's and doing dsl-hdinstall but now I am frugal and don't want to mess it up DSL looks like a very good O.S. especially because it has kept my old boat anchors going great.