In order to create a place for your party, you first need to create a Party Pass that you want to sell with your party place. You can read how to create a Party Pass.
If you have created a Party Pass, go to your Host Dashboard and click on "Manage Party Places".
Then click on "Create Party Place":
Afterwards, you will be taken to a page where you should fill in the details about your party.
Make sure to add a Party Pass that you want to sell with your listing:
After you complete all the field in a submission form, click on "List My Party Place" on the bottom of page in order to publish your listing. Your listing will be visible across the app then.