Ah yes. I have that one too, and mine works fine.
Here are the steps I go about doing it.
1. (especially if you are doing it yourself without another person's help) get a large bucket. Mine is huge, so there's no chance the hose will flip out of the bucket. I use more of like a storage bin.
2. Fill up the siphon in the sink. Have one hand on the vac, one hand on the end of the tube. Start filling up the siphon end. If water doesn't go through into the tube, sometimes tilting it will release air bubbles and water will start to move into the tubing.
3. As the tube begins to fill up, balance the siphon end above the tube end so water reaches all the way through the tube. Once it gets to the end, put your finger over the tube to cap it. Then fill up the rest, keep in mind you may have to tilt the siphon end vertically a little bit to release oxygen and get the water into the tube.
4. You will end up with your finger on the end of the tube filled up with water, and the siphon end not all the way filled up but only leaving a little air at the top.
5. Walk the siphon over to the tank and the bucket.
6. To get the water flowing, you will need to fill up the entire siphon. This is the difficult part sometimes. I place the entire siphon in the tank (along with a bit of tube because it won't fit otherwise. Keep the siphon vertical so that water can fill up the empty space. You now have the entire siphon part and tubing full of water. This is when you can start the flow.
7. Remove your finger from the end of the tube. The flow should work, unless there was a bit of air still in the tube or siphon.
Hopefully that helps. I always fill mine up at the sink, instead of doing it that crazy way of dunking it and such. For the flow to start, the only thing that needs to happen is that the tube and siphon are full of water to begin with. The flow will stop if there is a bubble somewhere in the tubing.
It may take some time to get the filling up part down right, it took me a while but you learn real quick what kinds of angles are best for filling up problem spots. Just remember that you can fill up the rest of the tubing by raising the height of the siphon end, then water will flow to the lower end.
I hope this isn't too confusing, and that it helped a little. If your siphon has a hole in it, that's another issue though.