There are several places you can go to. One is called a "gun store". It's a store where they sell guns. I suggest you wander around your area and look for a building with a sign that says "guns". Go into that building and ask for a Saiga 7.62.
There also exists things called "gun shows". They're similar in concept to gun stores. Follow the instructions given above.
Finally you can check something called "the internet". Ask around and find a friend who's heard of it. Explain your situation to them and ask for their help. You should have no trouble finding a Saiga 7.62.
I'm already preparing myself for your next round of questions that'll probably include "what's a 'trigger'?" and "where does the bullet come out?". Always happy to help in any case! :biggrin: