Hey Guys,
I wanted to kick in here and see if I could be of assistance. First off, @Framemanager, a few things with the first being, are you sure your Baud rate is actually set to match the printer. It looks like 25000 is the setting for the Mega. If this was not set correctly then you might not be able to send a command. To set it you can follow this gif!

From there you should be able to run the "Extrude command" from the extruder option at the top of the screen.

Let me know how that goes!