With just a few steps, you can create an app page that lets your Lightning Experience and Salesforce1 users access the most important objects and items in your custom app. Custom app pages are built using Lightning Pages.
Before creating your page, determine which components you want to include and the global actions your users need.
Create the Lightning Page.
Add actions to your page.
Activate your Lightning Page in the Lightning App Builder.
Activation lets you create a custom tab for your app page, set its visibility, and add it to the Salesforce1 navigation list and Lightning Experience app navigation bars all in one place.