Place the cursor where you want the index table to appear
Go to the References tab
Click Mark Entry for each term you want in the index
Select the text or place the cursor on the word you want to index
Click Mark Entry
Adjust the entry if needed
Repeat for all index terms
Place the cursor where you want the index table inserted
Go to the References tab
Click Insert Index
Choose the format and options you want
Click OK
Update the index when needed by right-clicking it and selecting Update Field