Click "Create in MetaEditor" in the context menu of the Navigator window in section Expert Advisors, Indicators or Scripts. MetaEditor can also be launched by pressing F4.
press ”Ctrl+N” or click on the ”New” button on the Menu bar.
In the MQL5 Wizard window, select Expert Advisor and click "Next" :
In the next window, type the Name you want to give to your EA in the Name box.
Clicking the “add” button and changing parameters in order to see which of the values can give the best result .
For Example, if you want to experiment with Stop Loss, Take Profit, and Moving Average Period settings, so you can define them at this point.
Double Click under the Name section and type the name of the parameter, then double click under the Type to Select the data type for the parameter, and double click under the Initial value section and type the initial value for the parameter.
Once you are done, it should look something like this: