Review the information in the Source field topic.
Then, do these steps:
In the Navigation Pane, click Lexicon, and then click Lexicon Edit.
In the Entries pane, click the desired entry.
In the Entry pane, if you cannot see the Source field (within each Sense), show hidden fields.
This Source field is different from the Source Form field (etymology).
In the applicable Sense, click the Source field, and then enter source information.