but bear in mind we were all beginners, so it was kept very simple so everyone could get it!
Theres more info here:

“Colotomy is a term coined by the ethnomusicologist Jaap Kunst to describe the rhythmic patterns of the gamelan. It refers to the use of specific instruments to mark off nested time intervals, or the process of dividing rhythmic time into such nested cycles. In the gamelan, this is usually done by gongs of various sizes: the kempyang, ketuk, kempul, kenong, gong suwukan, and gong ageng. The fast-playing instruments, kempyang and ketuk, keep a regular beat. The larger gongs group together these hits into larger groupings, playing once per each grouping. The largest gong, the gong ageng, represents the largest time cycle and generally indicates that that section will be repeated, or the piece will move on to a new section…..

That article goes into detail of common structures, and a means of notation…