All meditation requirements are almost the same, where you adopt yoga methodology in an isolated and quite environment to achieve the desired level in the meditation you are practising. Only thing different here is the breath, although the end result is the same.
To start with, you better wear loose clothing that makes you feel more relaxed. Then keep your spine straight but without rigidity. When you are free of tension, you will not get any other thoughts in your mind. In the beginning you are likely to be surrounded by some negativity but this is what you are going to fight against and if you are patient you can achieve maximum results.
Close your eyes just before starting the meditation and try to feel as much relaxed as possible. When required, you should take a proper time-out to keep your mind free of any disturbance or tension. You should meditate when you have free time and no one else is around to bother you during the entire process.
Start breathing through your nose and have a feel of the breath, fresh air, when it enters your lungs through nostrils. As you start the process you will start feeling more and more relaxed and this will complement your meditation process. In the beginning you might feel some difficulty in breathing but gradually you can feel it normal. This is not just limited to this type of meditation but true to all types. In the beginning one finds it very difficult to focus but as they go on with the meditation process, they learn to gain stability and master the technique.
Although this is not a mantra, you can choose the area where your feel sensation of your breath, either in the nose or back of your throat and see it as a concentration point. Keep your focus on the place where you feel sensation and this will help you build high level of focus. You can also count your breath to help yourself focus on the area, or else you can select a particular mantra that you can focus. The choice is yours.