To use the "minimized encounter summaries" feature, first you'll go to the "Clinic Options" section of "Clinic Settings" and select the feature:
Once that checkbox has been selected, you'll see a new option in the header under every patient's history tab:
Selecting that checkbox will change the view of the history, each exam summary will be constrained to just a few lines in height, with an option (the "+" button in the top right) to expand to full size:
As always, clicking the headline description (even from the constrained/minimized view) will display the exam details in the full "Visit" tab.