I just recently figured out how to use my syphon/siphon. Here are some tips from a fellow beginner.
1. Make sure you have the proper sized siphon for your tank, smaller ones are easier to use. With a smaller one, you may very well have to get your hands wet to get all the way down to the gravel in the tank.
2. Get a bucket and place it below the level of the water in the tank you plan to siphon.
3. Place the siphon in the tank full of as much water as you can get in it. Now, holding onto the siphon with one hand and the end of the tube with the other, you're going to "suck" on the end of the tube like a straw (I wipe mine off before I do this).
4. The water will fill the siphon head and tube very easily. Give it one good "suck" and then quickly point the tube downward towards the bucket. The water should begin to flow. Slowly at first, but gently push the siphon head up and down in the tank a couple of times, and that should get it going. If not, give it another big "suck." This WILL work.
5. To clean the gravel, once you have the water flowing, place the siphon head over patches of gravel and pull up. This should loosen up the dirt/waste in the gravel, which will then be sucked up into the tubing.
6. Once you have siphoned as much water as you need to, lift the siphon head in the tank until it has emptied. I usually refill the tank with a bucket, but there might be a more technical way to do this...