Salesforce Named Credential with Okta Auth

Salesforce has some built in authorization features that takes a lot of leg work out of coding. they call it Named Credentials. I have not come across any documentation on how to use Okta as IdP to connect my Salesforce app to another app.

We have set up Okta App. we are struggling with the Named credentials setup in salesforce.

We have tried to make this work but not making any progress. Any documentation out there that im unable to find.