Can I make a script which can work with multiple keys on my keyboard at the same time?
No, the software doesn't support pressing multiple keys at the same time. I've downloaded the installer and created a sample script using the Key function. I tried to simulate entering multiple keys, but couldn't find the exact procedure to do so or it's most likely not supported.
Use the following link to read more about the Key function available in the program: https://wiki.actiona.tools/doku.php?id=en:actions:actionkey