Reels are in 4/4 time which means there are 4 beats per measure and a quarter note (crotchet) gets one beat.  For example here is how you would count while playing the tune. The vertical lines separate measures.  Listen to Primrose Lass and repeat the words below the bar.

Track 26 Primrose Lass with Slow Rhythm (Mark and Collin McDonnell)

ONE two three four | ONE two three four | ONE two three four |

Or

WA-ter-me-lon | WA- ter-me-lon | WA-ter-me-lon | WA-ter-me-lon |

This is a very simple form of the reel, advanced drummers will commonly alter the emphasis on different beats to give the rhythm a lift but it will still have the basic 4/4 timing.

The manuscript (written form) would look like this:

Reel Practice Tracks

Primrose Lass Sheet Music (Click here to Download Primrose Lass PDF sheet music file)