How do they do it?

I’ve been looking at screenshots and videos and I was wondering how people make special poses and lighting in some of these shots. I see spartans posed with their rifles at rest and I see shots with dramatic lighting added somehow.I don’t know whether these shots are created with special tools I don’t have, are they made by designers, or on some web program, or what? Am I missing something in the Reach Forge mode that I should know about?

Plus I see custom Forge maps that seem to take more peices than are typically allowed to create. Is that just me or is there some trick behind that too?

I’m new to making my own creations in Reach. I dabble a little of course but I want to start making my own maps and creations in Halo. I love making things elsewhere and I’d like to start making my own neat stuff for Halo so any advice on this would help, thanks.