Disconnecting The Vari Flo Control Valve From The Lateral Assembly Center Pipe.

I followed the directions and put the sand in the filter, but now I can't put the cover back on and close it because the laterals won't go thru the sand. Because of that, there has to be a way to disconnect the control valve from the center pipe. That's the only way the pipe is going to stay in place. First the center pipe has to go in, fill it with water, put the sand in and then reconnect the control valve. Unfortunately I have no idea how to disconnect the control valve. I see a screw on the bottom, I'm afraid to undo that to disconnect it because I may break it and it may turn out not to be what I thought it was. If it is, great, but then how do I reconnect it without lifting the center pipe. The screw is on the bottom of the vari-flo. The only way to reconnect it is to life the center pipe. By doing that, it completely defeats the purpose of first putting the center pipe in before the sand. You know it would have made more sense if you made a seperate opening where you can pour the sand in, this way you wouldn't have to take the control valve off, except to remove the old sand. If it had a seperate opening you could put both the water and the sand in that way and then slide the cover over it to close it. The only other thing I can do is follow my friends advice and put the sand in through the skimmer. Obviously I have to hold the door closed so the sand does not go into the pool and this process will take alot longer. The filter would also have to be on so that the skimmer can pull the sand into the filter. I've looked and see no video for this specific filter on how to put the sand in. The only reason why I did it that way and not the way my friend said (whose had a pool for 12 years or more) is because the pool guy (a kid), told me not to.Very frustrated