With pump action shotguns, the shells are usually loaded in the bottom, and fed into the lower of the two chambers. And usually have a spring flap/door, to prevent dirt from getting into the gun. The hole on the side of the gun is the ejection port... it's not for loading the shells, but for ejecting them... when you pump the shotgun, you kick out the spent shell, and load a new one from the lower chamber into the upper chamber (barrel).

Your char looks good so far!