In the FX rack you can press the “Library” button to bring up a lost of the different types of FX processors. If you’re trying to duplicate a voice you will want to try the “delay” and the “ADT”.

The GLD will let you patch in external hardware as inserts if you have or know of a unit that does what you want.

You can’t add more than what is on the console without involving external hardware eg, digital I/O cards, computers etc. If you wanted to use a VST plugin running on a computer as an insert you could install a dante card in the console and use I/O port ins and outs to route audio into your PC > DAW > plugin and back into the channel. This might be a bit expensive if you only want one specific effect.

Chris