I did not even know the screen was movable! Does it just easily slide up and down? I assumed there was only one position as no half bowl groove like the DynaVaps.
It's a bit tricky, friction fit , just barely start to insert the screen, may need a allen wrench or condenser from the stem side to keep the screen from tilting or going too far in, may need to bend out 1 or more tabs. and pack/debowl gently