How to INNER JOIN an additional Table & Column

I have the code below to retrieve some values out of a system.  I need to add an additional table to this and need some assistance adding it.  The information that needs to be added is:
TABLE NAME: DOC_TYPE
COLUMN NAME: DOC_TYPE_NAME

DOC_TYPE.DOC_TYPE_ID = IN_DOC.DOC_TYPE_ID

Need to add DOC_TYPE_NAME to GROUP BY list and SELECT list.

>>>>>>>>>>>>>>>>>>>>>>EXISTING CODE>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
SELECT i.ITEM_ID,
       i.COMPLETE_TIME,
       iwh.FINISH_TIME,
       doc.DOC_TYPE_ID,
       u.USR_NAME, u.USR_FIRST_NAME, u.USR_LAST_NAME,
       count(i.item_id)as item_count
  FROM IN_WF_ITEM i
       INNER JOIN IN_WF_ITEM_QUEUE_HIST iwh
          ON i.ITEM_ID = iwh.ITEM_ID AND iwh.QUEUE_ID IN
                    ('301YTCF_006X864V3008KJ6', '301YTCF_006X8B4V3008LFK')    
       INNER JOIN IN_WF_ITEM_QUEUE_HIST iwh2
          ON iwh.ITEM_ID = iwh2.ITEM_ID
            and iwh.SEQ_NUM = iwh2.SEQ_NUM-1
            and iwh2.QUEUE_ID = '2000000BG7_00031H3LD522'
       INNER JOIN IN_DOC doc
          ON i.OBJ_ID = doc.DOC_ID
       INNER JOIN IN_SC_USR u
          ON u.USR_ID = iwh.START_USR_ID
 WHERE i.ITEM_TYPE = 1 AND i.QUEUE_ID = '2000000BG7_00031H3LD522'
and u.USR_NAME <> 'workflow.agent_001' group by i.item_id,i.COMPLETE_TIME, u.USR_NAME,u.USR_FIRST_NAME, u.USR_LAST_NAME, doc.DOC_TYPE_ID, iwh.FINISH_TIME