problem with hooking node add/edit form I wanted to hook node/add/patient-history form because I wanted to add ajax in that form.

Before adding Ajax I wanted to get field names correctly. So I tried this: 

function ajaxify_form_patient_history_node_form_alter(&amp;$form, &amp;$form_state, $form_id) {
  $form['field_history_patient_id']['und'][0]['#value'] = "Hello";
  // I also tried 
  $form['field_history_patient_id']['#value'] = "Hello";
}


They are not working. 

I am not sure if I am taking the field names incorrectly or missing something else.

Hook name seems to be correct because this one works:

  $form['actions']['submit']['#value'] = t('Save History');


I found some similar questions on stackexchange but with no answers. 

Any advice/links appreciated very much. Thank you.
I use this in my module to prepopulate the forms with data when hooking on FORM_ALTER:

$form['field_history_patient_id'][LANGUAGE_NONE][0]['value']['#default_value'] = "whatever";


But when defining the form it is enough to do :

$form['field_history_patient_id']['#default_value'] = "whatever";