Chell Chest White.stl and Chell Chest Blue A.stl need to be printed with support material.
Aperture Logo.stl is a two color print that can be done with a filament swap. Start printing in white, after 1mm swap to black.
Use the arms and legs from:
Assembly (Using the images for reference)
Slide Chell Chest Blue A down over the top of Chell Chest Black so the two fit snugly together. Press Chell Chest White in place on top of both of them.
Take Chest Blue B and fit it into place around the neck pin.
Slide Chell Chest Yellow down the neck pin, holding Chest Blue B in place.
Use glue as necessary to hold things in place.
You will also need:
The Smarty Pants Head:
The Sporty Long Hair:
The Portal Gun: