You can quickly deploy a new Custom Object in Jetstream from the Create Object and Fields page.
Jetstream allows creating one object at a time, usually you would do this prior to creating new custom fields for the object.
From the Create Object and Fields page, click the Create New Object button to open the modal to guide you through the process.
Choose the profiles and permission sets you would like to assign permissions to, and choose which permissions you would like to apply.
Configure your object. Jetstream will automatically populate the object plural label, API name, and Field Name fields for you when you modify the label to make the process simple. You can adjust the automatically populated values as needed.
Refer to Salesforce documentation on specific details for configuring a new custom object.
Once you start the deployment, review the results on the the Results tab.
Once you close the modal, the list of objects will be refreshed and the newly created object will be available for selection to create new custom fields.