Alright, first bear in mind that there are other options for mounting an RDS that are simpler to accomplish, such as the Ultimak or Attero mount. In the category of side rails, there's the traditional ones that require riveting (preferred), or screwing in. I'll cover the riveting one since it's the most involved.
First, you'll need either a shop press (Harbor Freight) and a Plinker type jig (AK-Builder or AK Machinist on the AKFiles) or a set of riveting jaws and bolt cutters (Toth Tool). Next, you'll need the side rail, which for your Draco an AKM pattern would be "correct". Next, you'll need to drill out the forward most rivet on the left side of the rear trunnion. Now place the rail on the left side of the receiver and slip a new rivet through the scope rail and into the hole. From there, eyeball that the top of the scope rail is level with the top of the receiver rails. The scope rail will not be level with the bottom of the receiver. Now using a set of calipers, measure the distance from the top of the receiver rail to the top of the scope rail at the rear most portion (where the rivet is) and ensure that the same measurement is at the front of the scope rail. Once they're the same, clamp the rail to the receiver and drill the center and left rivet holes into the receiver. Now crush the three rivets which will "permanently" affix the scope rail in place. Be careful doing this, as some of the riveting arms are not relieved very much and can bend the receiver at the receiver rail. This isn't really a concern using riveting jaws and a bolt cutter. In some cases, the heads of the forward and rearward most rivets will needs their heads filled down in order to allow a scope to slide on unhindered onto the scope rail.
Or, you could use the screw on type, which still requires drilling, or one of the other options mentioned earlier. You could also just pay someone to do it for you since it'll be cheaper. If any of this isn't very coherent it's because I'm on vacation and have a good buzz going.