Sure. I can answer that. It doesn't matter if there is an underlying crime. If you attempt to obstruct justice, that's a crime in and of itself.
To make a comparison:
you approach someone to kill your boss.
You pay them money to murder your boss.
But it turns out that was an undercover cop.
You get arrested.
You go to trial.
You go to jail.
Was there a murder? No.
Was there a crime? Yes.
You attempted to murder someone.
Let's say you decide to rob a bank.
You and your friends head off to the bank.
Your friends tell the cops your going to rob the bank.
You go in anyway to rob the bank.
The cops were waiting.
They arrest you.
Did you rob the bank? no.
Was a there a crime? yes.
You attempted to rob the bank.
In the Mueller report, there are 10 specific instances that are laid out where Trump attempted to obstruct justice.
Those are 10 specific crimes that need to be addressed.
Why wasn't Trump indicted?
Because of the standing DoJ policy that says a sitting President cannot be indicted, they must be impeached.
Mueller turned in his report so the House and Senate can move forward with impeachment proceedings.