First of all, welcome to the forums! All this information can be a bit daunting at first, so don't worry!
Here's an excellent tutorial from FrizzleFry; this is the one I used when I first joined.
http://405th.com/forums/index.php?showtopic=1648
Basically, you download the Pepakura Designer from the link in that tutorial, and then you download the files for the models you want to create. With a bit of help you'll be able to scale them to fit you, print the designs onto cardstock and assemble with a strong glue.
Once that stage is done, we harden the cardstock models with resin and fibreglass. Only fibreglass the inside so that the little details aren't lost. Resin goes on the outside.
Next, you apply Bondo or body filler to the outside which can then be sanded to give a smooth finish. After that, voila! Its up to you to primer and paint the piece how you like.
Hope this helps, PM me if you have any other questions or need anything, we're all here to help :]
Good luck!