What happened on the seconed day-Saturday

Jesus died on calvary on that Friday. My question is what happened between that Friday, and that Easter Sunday. The ultimate question is what was Jesus doing? Where did he go and what was accomblished?

When Jesus died on the cross he said it is finished. That was the ultimate part but something else happened. When he went into Haddes(Hell) unloosed the keys to captivity. All of the people that were on the good side of Hell called Haddess were the great saints such as Abraham, Moses, and all the other people that tried to keep the Commandments. When Jesus went down there it was said that saints were even seen walking about. This was amazing. The devil thought that he had Jesus and that he would not be able to get pass the captivity of Hell, but he rose with all power in his hand.

If you have more feedback let me know. I don't have all the answers.