Help Request

I am working on learning G-Max (again lol) and I am building a Mk 1 Vickers Wellington.

My problem is around see through things like the prop discs (prop0_blurred) and the glass. How do you make these things? Is it with texturing or do you tell G-max that certain poly's or objects have a lower opacity than others?
I have read through the Various tutorials and I must be missing something
Thanks in advance.
Will

My problem is around see through things like the prop discs (prop0_blurred) and the glass. How do you make these things? Is it with texturing or do you tell G-max that certain poly's or objects have a lower opacity than others?
I have read through the Various tutorials and I must be missing something

Thanks in advance.
Will