Convert custom indicator to EA (expert advisor) - Metatrader 5

Hello there, I have a custom indicator that gives sell and buy alerts. I want to convert it to EA that convert these alerts into orders as follows: 1) when a buy signals comes, it closes the sell order and opens a buy order. 2) when a sell signal comes , it closes the buy order and open a sell order. Depending on these two rules above: 1) The maximum opened orders at the same time is always only one trade for each paper that the EA works. 2) there is always a trade opened. 3) I have to be able to set a default lot size to the orders. 4) I have to be able to set money management as i wish. Note : when the EA is launched it must check if there is order opened or not, to make sure not to open more than one order at the same direction. ## what I need is to convert the code itself from an indicator code to EA code ( the use of icustom function is not allowed ) ## You can contact me if any further information is needed.