Custom Google Search - Results Sort

Hello,

After installing and configuring Custom Google Search, I did not see anything relevant to results sorting for relevance/date. Any suggestions on how to get sorting to work? On our main site, where we also use Google Search, a sort button is displayed in the top right of the results.

Main Web Site (with sort button):
https://www.union.edu/search/?q=muse#gsc.tab=0&gsc.q=muse&gsc.sort=&gsc.page=1

Plugin in use (no sort button):
https://muse.union.edu/newsarchives/?s=test

Thanks!
Mina