To create a new draft:
Open the Asset Store Publisher Portal and navigate to the Packages in the left navigation bar.
Click Create a package button on the right top corner of the page.
The Create new package page appears.The Create a package window appears. Enter Package name, select a Category, and then click Create my package.
Next, the Edit package page will appear, displaying the details of the package.You can fill out the package details before or after you add your Assets to the package draft.
When you have a package draft, you can add and upload your Assets to it.