Two year old thread. If you use Google you will fund ways to install barrels using threaded rods through the bore. You do not state if the front rivets are in place but a set of Harbor Freight bolt cutters can be fashioned to squeeze the front trunnion rivets etc.
You Tube has hundreds of how to videos with simple or homemade tools etc.
Putting together a SKS would require headspace gauges, barrel vise etc. Not plug n play nor is the AK assembly.