You should be able to use their token,Once a session token is obtained, it can be passed into the OpenID Connect authorize endpoint in order to get an Okta session cookie. Executing this flow will set a cookie in the end-user’s browser and then redirect them back to the redirect_uri that is passed into the request. I'll go ahead and attach a link that will go explain this in detail.
Can you please be more descriptive? I am also dealing with exact same use case. Our app doesn't have UI involved so its not browser related.
What I need is, once user is authecticated to OCTA via primary authentication API and get the session token, what would be the next step or API calls which would be require to get an access of other pre-configured apps in Okta. Salesforce.com (Federated ID) app is a assigned application to Okta users.