Here's a rare teaching by Ajahn Sao, the teacher of Ajahn Mun, on the topic of Buddho meditation...
In our day and age, the practice of going into the forest to meditate and follow the ascetic dhutanga practices began with Phra Ajaan Sao Kantasilo, the teacher of Phra Ajaan Mun and, by extension, Phra Ajaan Singh and Phra Ajaan Lee. Phra Ajaan Sao was inclined to be, not a preacher or a speaker, but a doer. When he taught his students, he said very little. And those who studied directly under him are now elders who speak very little, who rarely preach, having picked up the habit from their teacher. Thus, as Phra Ajaan Sao was not a preacher, I would like to tell you a little of the way in which he taught meditation.
How did Phra Ajaan Sao teach? If it so happened that someone came to him, saying, "Ajaan, sir, I want to practice meditation. How should I go about it?" he would answer, "Meditate on the word 'Buddho.'"
If the person asked, "What does 'Buddho' mean?" Ajaan Sao would answer, "Don't ask."
"What will happen after I've meditated on 'Buddho'?"
"Don't ask. Your only duty is simply to repeat the word 'Buddho' over and over in your mind."
That's how he taught: no long, drawn-out explanations.
You can read more about it here: http://www.accesstoinsight.org/lib/thai/phut/sao.html