The old Opus 5 manuals are here ...not up to date, but still useful.
viewtopic.php?t=908 I have them compiled into one huge pdf, and use the search facility. One of the best sourced of help is the Opus help in the menu. There is a help for scripting and it contains most of what's in the manuals. The opus script manual is there---a good place to start.
'image of a counter??' do you simply want a display showing a count/ 1,2,3,4,5 etc???
does it need to be accurate?? or do you want a more visual display??
Attached is a very quick example of a clock using actions. it has start/stop/pause/resume and reset. hopefull it will give you some ideas.
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Rgds
Sandy