Go to scholar.google.com and click on the hamburger menu in the upper left:
Then click on Setting, and then click on Library links and do a search for Washington State University and select all options (except the ones for WSU campuses other than your own if you see any ;-) Note that I have also selected Open WorldCat; this will offer you the chance to move from the freely available Open WorldCat to the WSU Libraries WorldCat Discovery catalog (this is a great resource for locating books not available in Search It or via Summit). Open WorldCat should be there by default, but if it is not just search and add your WSU library links, then do another search for Open WorldCat and add it then.
While you are on the Settings page, why not change your Search Results to show 20 results instead of the default ten. Also, if you click on the Account link you will see a checked option for "Signed-in off-campus access links." This is provided by Google Scholar, not the WSU Libraries, and basically remembers your WSU log-on credentials even if you are off-campus in certain circumstances.
Every so often you may need to re-do these settings if you are not seeing the FindIt@WSU button in your results (sometimes a browser update or history/cookies flush erases your settings) - note also that if you flush your cookies automatically your setting won't be saved. Also note that the FindIt@WSU button will not show up for every result.