Newbie - Render debug objects - World to Local coordinates

[Gibbon99]

I'm still learning about how matrix and coordinates work so please excuse this basic question.

I'm using GLM and OpenGL and have physics working in a 3d space. Now I would like to render the collision objects to check everything is ok. I note the doco says that the returned vertices are in World Space.

I have looked through the testbed application, and it seems to be doing some sort of inverse matrix magic - which I don't understand.

How do I go from the debug World Coordinates into something I can render using the exisitng pipeline - or what MVP do I need to perform in a shader ?

I can render them now - but they are only appearing as flat rectangles on the screen as the coordinates are in the wrong space. An example in c++ would be very useful.

Thanks