So an absolute phrase describes an entire clause.
The crane hung limply into the clear blue sky, the house was ugly before it was destroyed.
The bolded part is the absolute clause. It is modifying the entire sentence. The noun house begins the absolute phrase and then it is followed by an adjective, ugly, and then a preposition follows, before it was destroyed. I believe that is how most absolute phrases are formed.
I hope this helped and good luck.