Yesterday I bought a glass pipe, it looks like this:

|.............|
|.............|
|\.........../|
|..\......./..|______________________________________
|.............______________________________________
|............/
..\______/

Am I right in thinking that you set it up like this:

|.............|
|.............|
|.\ XXXX /|<-----WEED
|..\XXXX/.|.
|~~~~~~|<-----WATER
|.............|______________________________________
|............. ______________________________________
|............./
..\______/

or is that wrong?

I assume you need something to keep the weed on top?