Decide on the height of the loft; we chose 4' since the closet is 8'
Install your supports, screwed to the studs in the walls and into anchors if additional support is needed.
Create a 2x4 frame.
Cut a sheet of plywood the dimensions of your closet space. Depending upon the size, you may need to cut it in half in order to install. We were able to install ours as a single sheet. We did not screw our plywood down, allowing access from underneath if ever needed.
We added a facer on the front of ours and also required a spacer in between the support and the facer to provide us with the space we needed to install the "window" so that it remained in the doorway to the closet and didn't interfere with the mattress.
The "window" was made with an air nailer. Simply purchase lengths of wood in the dimensions you would like to use and cut it to size, lay it out and nail it together. Use glue as well to provide added strength to the joints.
Paint or varnish your window and install it with screws. Ensure it is a very tight fit into the space, gives it lots more strength.
The handle you see was bought many years ago for a play ground set but I'm sure you can get them at Canadian Tire or Home Depot. The ladder we made ... lengths of wood for the sides, dowels, a spade drill bit (the same size as the dowels you choose. Decide how many dowels you want to use and mark your wood on both pieces. Drill through the outside to the inside of your side rails with a small drill bit. Then, use your spade bit on the inside of the rails to create a pocket for the dowel to sit. Use glue to add strength and screw in your dowels.
Ikea Picture Ledges: http://www.ikea.com/ca/en/catalog/products/70177062/
Wall Decal from Etsy.com. Find on that fits and compliments your space.
Mattress: Ikea Foam Mattress ... Cut to size. http://www.ikea.com/ca/en/catalog/products/20139751/
The finished product:
You can duplicate the bottom with the same materials as above if you are looking to accommodate two children.