Disclaimer: I usually don't use C# in Godot.
Autoloads get attached to an invisible node with the same name under the scene tree root. So you could get it using var console = GetNode("/root/Console")
.
You'll then need to use console.call()
as described in the docs. I think you might be able to chain them like you do in gdscript: console.call("addCommand", ...).call("setDescription", ...).call("addArgument", ...).call("register");
EDIT:
Seems like you can't just chain call
together, you'll need to do some typecasting in between e.g.
var temp = console.call("addCommand", ...) as Godot.Object;
temp = temp.call("setDescription", ...) as Godot.Object;
temp = temp.call("addArgument", ...) as Godot.Object;
// etc