buy trade NOT based on candle (price)

[famuzz]

hey there, i am a newbie to this.
starting out with a test project: when 7sma >X 12sma: buy / when 4sm <X 7sma: close trade

when analyzing the back test i noticed that it doesn't open the trade when the SMAs cross, but when the closing price of the candle is created. what do i have to do to execute the BUY the very millisecond the 7sma crosses above the 12sma, vice versa: how to close the trade the very millisecond the 4 crosses below the 7 sma?

thanks for your input, i am sure you can fix this in a second

f