These options are available in the Settings tab of your dashboard.

Your organization name will appear on the Public Events Feed, so keep that in mind when you create your name. 

The event feed URL contains the URL slug, which is the part that you can edit.

The slug is the part of the URL that is unique to your organization and will be included in every URL for your pages.

Make sure you pick something short, use lowercase letters, and do not include spaces or punctuation.