How do I pay import duties on DAP shipped item?

Hello All,

I purchased a small electronic auto part through Alibaba. It has arrived and shipped DAP. It arrived at the house by USPS. I have paid sales tax and

Shipping but have not paid any duties (yet).

Can anyone help

Me understand how I am to pay the duties?

Alibaba was the only place in the entire internet space that had this part so I took a chance and ordered it. It arrived timely. Now I just need to understand how to pay the duty???

For reference item was about $150 and it is my under standing that I still have the honor of paying the duty…