Basically Irunguns is a company that imports guns into Canada. They have 2 websites, the Canadian site
www.irunguns.ca and the American site
www.irunguns.com
So for instance you want to buy that Raging Bull from the .com site. Add the gun to your shopping cart and proceed to checkout just like any other site. When filling out some of the info during checkout look to the left of the page for some pointers from Irunguns as to what info to put in in certain fields. Fill in your information, address and everything else, including payment info, hit checkout and your done with the .com site. You'll receive an invoice form the .com site via email.
Next you have to fill out an importation form, you can find a link to this form along the left side of the pages of the .com site. Fill out that form the best you can and send it IRG.
Now the wait begin, IRG does one import per month. Usually in the 3rd week of the month. So if you were to place an order in January your revolver would come into Canada around the 3rd week of February. Once the gun is in Canada, IRG will email you and invoice so you can pay the taxes and shipping to your door, the tax is 5% BTW. And then they ship you your gun from Alberta.
That's basically the gist of it.