Not stupid Adrian, it just takes a bit to get the concept.
Right Clicking on the interface shows menus of lots of modules (bidules) you can add. You only need a few to run a good setup though.
1. R-click choose midi and select a midi in device (either a software connect with DAW or hardware device. I run DP and choose Bidue 1 (in)
2. R-click choose a midi splitter (from midi menu) and place underneath midi module.
3. Click on little white box at bottom of midi bidule to same on top of splitter.
4.R-click and choose a VST instrument> VSL. Or an AU Musical device and same. Do step 3 procedure and connect from splitter to Instrument.
5. R-click and Choose a stereo mixer from Mixing menu and connect to instrument as in step 3. I use a 16 ch mixer and give each instr it's own stereo input.
6. R-click and choose Audio Device and choose your soundcard from OUTPUT. Connect to mixer Stereo outs.
7. Put each of these Bidules/Modules underneath the previous so routing is clear. There are many other options for bidules but this setup is all I use for VSL VI.s.
Have fun