This weekend I am going to try partial suspension. So I will have to tie a few scarves together to get something to suspend myself with. Then I'll tie one end of the scarf to the door (is a regular knot ok?) and make a slip knot on the other end of the scarf and throw it over the door.
For tying the scarf to the door (handle/knob), you can use pretty much any knot that won't come undone. A slip knot will work as you can pull it tight before throwing it over the door. As you are using scarfs, can the door be closed after they have been thrown over? If so, this may help to take some of your body weight off the door handle/knob and the door should take most of the weight.
From there I am a bit confused. I think I will stand on a step stool and put my head in the noose and make sure it is completely tight. Then I just kick the stool?
No step stool required. You are not trying full suspension but partial. This means that your feet will be on the floor supporting your weight before you start. If you have read the [Resource] How to hang yourself thread, then you will have noticed a couple of variations. One is to slide down the door until your full weight is supported by the ligature (scarf for you), the other is to lean forward into the noose. In both cases, the theory is that your weight will compress your carotid arteries blocking off the oxygen supply to your brain, and you should pass out quickly. The 'lean forward' method can be done from either a standing or kneeling position. Here's a good video from the thread:
How do I prevent standing up?
Once you are unconscious, you will not be able to stand up. However, if your SI kicks in before you're unconscious, then you most likely will stand up or at least try and support yourself.
How do I make sure I get enough pressure on the right spot of my neck? I tried looking for the spot by my Adam's apple and pushed hard and started feeling faint. Does that mean that I have the right spot?
That sounds like you have the right spot. As long as the pressure from the scarf is in the same area, then you should be ready to go. I've heard of some people tying knots to focus the pressure in the right area, but this shouldn't be necessary. You can also practise by placing the noose around your neck and pulling up on the scarf. I can't find the reference at the moment, but if/when I do, I'll edit or post.
Does the knot go infront or behind my neck?
I've seen both used, and also with the knot at the side of the neck. The most typical way is with the knot behind the neck.