[keycloak-user] Is it possible to complete a login process with program ?

Hi, there,  I am new in this domain so pls help me even my question looks too naive.  What I want to do is as below: 1) Add a user with RESTful  API . 2) get the token with direct access grant . All above will happen with  program.  We can add a user , but  can not get the token . It seems the user can not  login in .  We missed something ? Is there any example code ? Thanks in advance.  Mai