You're going to need to figure out
- what you want to display (E.G. seconds, minutes, hours)
- how you're going to pass that value to OBS (you mention "txt", so presumably it can read a text file)
- how you're going to speak the values (I.E. which command phrases you're going to need)
- how you're going to calculate the difference between the current time and the target time (including whether the target time falls within the current day or not)
- how you're going to actually count down to the target time once you know how much time needs to elapse
VoiceAttack implements the
DateTime datatype (as "date" variables), which can be converted to ticks for math, however in this case you'll likely want to use the
TimeSpan datatype instead of that conversion, which will require an inline function.
I don't know why you surmise that this is "something simple", as working with time rarely is. Good luck.