Tubes can be placed anywhere in the machine that they will fit.  Left click to pick up a tube from the tray on the console.  Your cursor will change to show the tube you are holding.  Move the mouse cursor over the machine; green squares show valid locations to place the tube you are holding and red squares show invalid locations.  Left click to place the tube into a valid location of the machine.  Left click again to pick up the tube.  You can drop the tube you are holding in the tray by left clicking in the drop area.

To move the camera around in the room, you can click on a location in the Radar at the left side of the HUD.  You can also move around by using the arrow keys or the WASD keys on your keyboard, or by dragging the mouse at the edges of the screen.  You can use the + and - buttons next to the Radar to zoom in and out, or use the mouse wheel, or the Q and E keys.
