I don't place trades via Excel. I currently place the trades manually. I'm not doing anything near high frequency...holding one to several days per instrument.
The algo can generate a list of 'times' and price levels it believes are probable highs/lows.
I do use excel to update the price data via the WEBSERVICE function and a data provider's API.
I did a quick search and found a link you might be interested in. Again, I haven't done this:
How To Create An Automated Trading System In Excel In 10 Steps
https://jbmarwood.com/automated-trading-system-in-excel/
