Um. Just dragging out the intervals between the words that are being chanted. Eg. "Na".................. "Na"... Repeat "Mo"... A Mi Tuo Fo. I only do one complete cycle. Surprisingly took more than 24min
It's important to note, what I learnt from Vipassana from the teacher, was a focus on belly breathing, which has several advantages. But, nose breathing is pretty cool too. I'm chill about it. It takes some time to practise belly breathing, to make it sort of automatic. One way, is to put a fist under the palm, and feel the rising and falling of the belly. My personal preference is the upper belly.