Hi Jennifer,
Integrating with Azure AD B2C is a bit different than with Azure AD.
Daniel already share this link where you should start. You need to setup first the user flows you want to have (sign in, sign out, ...) and then redirect your user using them from OutSystems. On those flows you can configure the callback endpoint so Azure is able to send you back the outcome of that flow.
Please let me know if this is enough for you to start.
Regards
Joao