I want to use Open edX at my institution

The Open edX software is open source, anyone can use it to deliver online education.  There is no need to coordinate with edX.  EdX does not offer hosting services beyond the institutions with courses on edx.org.

There are no limitations on how you may use the Open edX platform.  You may limit who can access your courses, and you may charge money if you wish.

There are a few places to start:

You will need an Open edX installation to use. There are a few ways to get an installation, outlined on the Installation Options page.  Many people find it best to use a service provider to install and operate an Open edX instance for them.  Installing and running an Open edX instance can be complex.

You will need to create courses.  Open edX Studio is an easy-to-use authoring tool.  The courses you create are your property.  Edx.org has a series of courses about how to best use Studio to create Open edX courses: edX Course Creator XSeries.