Well,
1. Open the MetaEditor program. This program is typically included with the MetaTrader 4 trading platform.
2. In the MetaEditor program, click on "File" in the menu bar and then select "Open" or use the keyboard shortcut Ctrl+O.
3. Navigate to the location where the expert advisor file (.mq4 or .ex4) is saved on your computer.
4. Select the expert advisor file and click on the "Open" button.
5. The code of the expert advisor will be displayed in the MetaEditor program. You can navigate through the code, review it, and make any desired changes.
that might be helpful