I have one of those with the buckles at the back removed.

I wear it with my three colour forest DPM kilt - and from time to time I take it apart and carefully polish the brasswork, then wash it, dry it and put it back together.

I think that the two ends should be folded to about the same depth, and the sliders should be pushed hard against the buckle, but there is no rule about which side the clip should go.

I have had mine about 40 years now, they are very hard wearing.

It was originally black -boot polish I think - then when scrubbed it went white (combination of paint and Blanco perhaps) and over the years has gradually darkened towards what I assume is the original colour.