You go to your local county clerks office and ask for the paperwork. You complete it, pay the fee and file it, and serve him (via certified/return receipt mail) with your complaint. The only thing you need is his last known address

The courts will then schedule a hearing, you show and present your case, and it's done and over with. You do not need his permission or acknowledgement in order to proceed or be granted a divorce. With no children or joint property, it's really as simple as that.