[RerRibreLok]

Ajahn Chah explains how to use Buddho here:


Just Do It! - A Dhammatalk by Ajahn Chah


"Just keep breathing in and out like this. Don't be interested in anything else. It doesn't matter even if someone is standing on their head with their ass in the air. Don't pay it any attention. Just stay with the in-breath and the out-breath.

Concentrate your awareness on the breath. Just keep doing it.Don't take up anything else. There's no need to think about gaining things. Don't take up anything at all. Simply know the in- breath and the out-breath. The in-breath and the out-breath. Bud on the in-breath; dho on the out-breath. Just stay with the breath in this way until you are aware of the in-breath and aware of the out-breath....aware of the in-breath....aware of the out-breath.

Be aware in this way until the mind is peaceful, without irritation, without agitation, merely the breath going out and coming in. Let your mind remain in this state. You don't need a goal yet. It's this state that is the first stage of practice.

If the mind is at ease, if it's at peace then it will be naturally aware. As you keep doing it, the breath diminishes, becomes softer. The body becomes pliable, the mind becomes pliable. It's a natural process. Sitting is comfortable: you're not dull, you don't nod, you're not sleepy. The mind has a natural fluency about whatever it does. It is still. It is at peace. And then when you leave the samādhi, you say to yourself, 'Wow, what was that?' You recall the peace that you've just experienced. And you never forget it."

continued here:

http://www.ajahnchah.org/book/Just_Do_It_1_2.php