Map user informations coming from identity provider to user in keycloak

How can I do the mapping between the attributes coming from GitHub (idp) and these of Keycloak (identity broker) ?
How to see the token exchanged between idp and identity broker with attributes. For example in keycloak we have “First Name” and “Last Name”, how can I map them with GitHub information ?
Without code, using Mappers in Realm Setting Clients or Identity Providers Mappers
Thank you