It goes under on tick , if used on top it will only activate once when a new candle opens , and only once . Then it wont check contiions at all until the next candle is opended, so it blocks everything else.
And if used below your main conditions and above buy/sell blocks it will check the conditions on every tick and when its true it will only pass once , and that can be anywere in the spand of the candle time, at the beggining middle or end of it .