If you have a retailer or distributor account.
Retailers create a publish Switches to the Switch Marketplace. If you are a retailer or distributor and have created and published a Switch it will automatically be installed and available in your Export Factory for use.
If you have a manufacturer account.
To install a retail partners Switch go to the "Switch Marketplace" - there is a link in the upper right corner of every page when you are logged into your account. Once there you can search for a retailer, and click the "Install" button. You must have a Switch subscription to be able to install a Switch. You can get a Switch subscription by going to the Plugin Store link which is also available in the upper right corner of every page while you are logged into your account.