What don't you understand? I have one and the diagram is useless, I'll try and help. The line from your co2 tank goes to the bubble counter. The line coming out the side of the bubble counter goes to the center john guest fitting, This line needs a valve in it to adjust the flow in the reactor. The last line goes on the outer john guest fitting and also needs a valve to adjust the effluent drip rate into your sump or where ever your going to have it drip! You'll have to find a sweet spot in adjusting the valves to control the flow Thur the media and the amount of effluent dripped into the sump Hope this helps.