Re: about participle clause
It probably works well for a lot of actions, but not for states of being. It would be used to say that it's because the first action is complete, the second action is now possible.
Having stamped the letter, she mailed it.
Having knocked on the door, he opened it.
Having washed her hands, she started cooking.
But it's often not the most natural way to express the sequence. "She washed her hands and started cooking" is just fine.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.