Once the Ten Commandments were etched in stone, they became law; a Godly law. But, how does that transpire into man's law? Could you do something to man that was not against God? Is there a way around His law and still get away from helping man? God knew man's heart and knew his intentions. He knew what man would do if there was some loop hole or way out of something. So, God continued with explaining what the law meant. And since Israel was a stubborn nation, then punishment and atonement for breaking the laws needed to be strict. Israel was God's chosen people. They should have known the power of God yet somehow they remained worldly. He would put a stop to it. This is why chapters 21-24 in Exodus are long winded, extreme, monotonous, dare say...boring, along with Leviticus and Deuteronomy.
Almost every aspect of life was written down on how to treat your fellow man. The first four commandments dealt with what your relationship with God should be. The other six deal with your relationship with other people. But notice when the covenant is expanded most of the laws deal with man. When God laid down the law about our relationship with Him, He needed no to expand. He is the Lord, nothing else will do, remember Him and Him only! Stray outside that and you have a problem. But He knew we would do things to each other and needed guidance. These chapters tell us how do deal with servants, injuries, property, social responsibility, justice, mercy, the sabbath and celebration days. Each topic mentioned has its own subtopics as well.
In the end though God tells His people He will protect them if they abide by the rules. He sends an angel out before them preparing their way. Who is the angel? No one knows. It could be any of them but verse 23:21 says he will not forgive your rebellion since my Name is in him. Is that a hint that it could be Christ or is it symbolically saying there is no excuse for rebellion against something from God? You have to be the judge there.
The covenant is finally confirmed with the sacrifice of a life. A young bull (several of them) was sacrificed to claim the testament in blood, the life force, the essence of being. And as a final witness to this covenant God showed Himself to Moses and all the elders of Israel. They ate with Him and had fellowship. But God would not do this all the time. He is too holy to be seen by all so the next step was to build a place where God could meet His creation; the tabernacle.