As a contributor, you can also add the assets directly using Salesforce plugin. Follow the steps to import the metadata from Salesforce directly:
Click on the Add Play button which is location at the top right of screen.
This will open a popup with selection for importing method. Lets choose Salesforce and select the instance for your salesforce org.
Enter your Salesforce credentials:
Allow the application to get access to your details and Salesforce system.
The Playground application will fetch the available Salesforce metadata and display for selection. Select the type of components or metadata you want to include in your asset.
From the selected metadata types, pick the components that should be part of the asset. The list can be collapsed to access all the records.
Name the Play
Provide a meaningful name for the play.