If you need to clear the browsing data/cache on your Chromebook here is a quick guide

1.  Click on the three vertical dots in the top righthand corner of Chrome.

2.  You will now see a dropdown menu, from here scroll down to the "More tools" option, another submenu will appear next to the dropdown and you should see the "Clear browsing data" option, go ahead and click this setting.

3.  The "Clear browsing data" window should open up in the center of your screen.  Within this window you should see the "Time range" dropdown, by default this will say "Last hour".  Go ahead and click the dropdown and change this setting to "All time".  

4.  Once you click "All time" the dropdown should disappear and you should have the following screen showing, if your screen matches go ahead and click the blue "Clear data" button.  After you click the "Clear data" button the "Clear browsing data" window should close and will send you back to the settings page.  At this point your browsing data/cache should be cleared.