connect to Restful service using JWT (external partner)

I am new to JWT.
We have middleware system that connects to external partner client. And this is what their ask is to connect to their Restful service :

The client may choose to use bearer authorization into the network APIs. When using bearer authorization for the /platform endpoint, the client must use the /token endpoint to obtain the Access Token for use.
The client’s API must first authenticate with the OAuth Server using HTTP POST to the /token endpoint.

The network exposed API’s can be mutually authenticated via TLS and should be secured using either signed JWT, private_key_jwt or the Access Token issued by the network. This requires an onboarding step of exchanging certificates and establishing the open ID connect (OIDC) client_id between the network and the Client.
For the network endpoints, the network will support API authentication using both basic authentication and OAuth2 (2-legged OAuth). This will involve Early Warning issuing a client_id to the Client during onboarding.